diff --git a/src/pretix/base/forms/__init__.py b/src/pretix/base/forms/__init__.py
index 339b3fe379..48cf00365e 100644
--- a/src/pretix/base/forms/__init__.py
+++ b/src/pretix/base/forms/__init__.py
@@ -50,7 +50,7 @@ class SettingsForm(forms.Form):
 
     def __init__(self, *args, **kwargs):
         self.obj = kwargs.pop('obj')
-        kwargs['initial'] = self.obj.settings
+        kwargs['initial'] = self.obj.settings.freeze()
         super().__init__(*args, **kwargs)
 
     def save(self):
diff --git a/src/pretix/base/i18n.py b/src/pretix/base/i18n.py
index f4d82e71f9..69df674e5a 100644
--- a/src/pretix/base/i18n.py
+++ b/src/pretix/base/i18n.py
@@ -3,7 +3,8 @@ import json
 
 from django import forms
 from django.conf import settings
-from django.db.models import SubfieldBase, TextField
+from django.core.serializers.json import DjangoJSONEncoder
+from django.db.models import Model, QuerySet, SubfieldBase, TextField
 from django.utils import translation
 from django.utils.safestring import mark_safe
 from typing import Dict, List
@@ -233,3 +234,15 @@ class I18nTextField(I18nFieldMixin, TextField, metaclass=SubfieldBase):
     Like I18nCharField, but for TextFields.
     """
     widget = I18nTextarea
+
+
+class I18nJSONEncoder(DjangoJSONEncoder):
+    def default(self, obj):
+        if isinstance(obj, LazyI18nString):
+            return obj.data
+        elif isinstance(obj, QuerySet):
+            return list(obj)
+        elif isinstance(obj, Model):
+            return {'type': obj.__class__.__name__, 'id': obj.id}
+        else:
+            return super().default(obj)
diff --git a/src/pretix/base/models/auth.py b/src/pretix/base/models/auth.py
index aef87c5d66..f58260a565 100644
--- a/src/pretix/base/models/auth.py
+++ b/src/pretix/base/models/auth.py
@@ -5,6 +5,8 @@ from django.contrib.auth.models import (
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
+from .base import LoggingMixin
+
 
 class UserManager(BaseUserManager):
     """
@@ -30,7 +32,7 @@ class UserManager(BaseUserManager):
         return user
 
 
-class User(AbstractBaseUser, PermissionsMixin):
+class User(AbstractBaseUser, PermissionsMixin, LoggingMixin):
     """
     This is the user model used by pretix for authentication.
 
diff --git a/src/pretix/base/models/base.py b/src/pretix/base/models/base.py
index cea57f989a..658ca12b6d 100644
--- a/src/pretix/base/models/base.py
+++ b/src/pretix/base/models/base.py
@@ -1,3 +1,4 @@
+import json
 import uuid
 
 from django.contrib.contenttypes.fields import GenericRelation
@@ -5,6 +6,8 @@ from django.db import models
 from django.db.models.signals import post_delete
 from django.dispatch import receiver
 
+from pretix.base.i18n import I18nJSONEncoder
+
 
 def cachedfile_name(instance, filename: str) -> str:
     return 'cachedfiles/%012d.%s' % (instance.id, filename.split('.')[-1])
@@ -29,10 +32,18 @@ def cached_file_delete(sender, instance, **kwargs):
         instance.file.delete(False)
 
 
-class LoggedModel(models.Model):
+class LoggingMixin:
     logentries = GenericRelation('LogEntry')
 
-    def log_action(self, user, action, data):
+    def log_action(self, action, data=None, user=None):
+        """
+        Create a LogEntry object that is related to this object.
+        See the LogEntry documentation for details.
+
+        :param action: The namespaced action code
+        :param data: Any JSON-serializable object
+        :param user: The user performing the action (optional)
+        """
         from .log import LogEntry
         from .event import Event
 
@@ -41,7 +52,13 @@ class LoggedModel(models.Model):
             event = self
         elif hasattr(self, 'event'):
             event = self.event
-        LogEntry.objects.create(content_object=self, user=user, action=action, data=data, event=event)
+        l = LogEntry(content_object=self, user=user, action_type=action, event=event)
+        if data:
+            l.data = json.dumps(data, cls=I18nJSONEncoder)
+        l.save()
+
+
+class LoggedModel(models.Model, LoggingMixin):
 
     class Meta:
         abstract = True
diff --git a/src/pretix/base/models/orders.py b/src/pretix/base/models/orders.py
index 18f58bc62b..b42dcd1862 100644
--- a/src/pretix/base/models/orders.py
+++ b/src/pretix/base/models/orders.py
@@ -2,7 +2,7 @@ import random
 import string
 from datetime import datetime
 
-from django.db import models
+from django.db import models, transaction
 from django.utils.timezone import now
 from django.utils.translation import ugettext_lazy as _
 from typing import List, Union
@@ -177,14 +177,6 @@ class Order(LoggedModel):
                 return True
         return False  # nothing there to modify
 
-    def mark_refunded(self):
-        """
-        Mark this order as refunded. This sets the payment status and returns the order object.
-        """
-        self.status = Order.STATUS_REFUNDED
-        self.save()
-        return self
-
     def _can_be_paid(self) -> Union[bool, str]:
         error_messages = {
             'late': _("The payment is too late to be accepted."),
diff --git a/src/pretix/base/payment.py b/src/pretix/base/payment.py
index d94d6eee71..6bc2e00561 100644
--- a/src/pretix/base/payment.py
+++ b/src/pretix/base/payment.py
@@ -359,6 +359,7 @@ class BasePaymentProvider:
 
         :param order: The order object
         """
+        self.order.log_action('pretix.base.order.refunded')
         return '<div class="alert alert-warning">%s</div>' % _('The money can not be automatically refunded, '
                                                                'please transfer the money back manually.')
 
@@ -379,7 +380,9 @@ class BasePaymentProvider:
         :param request: The HTTP request
         :param order: The order object
         """
-        order.mark_refunded()
+        from pretix.base.services.orders import mark_order_refunded
+
+        mark_order_refunded(order, user=request.user)
         messages.success(request, _('The order has been marked as refunded. Please transfer the money '
                                     'back to the buyer manually.'))
 
@@ -440,7 +443,9 @@ class FreeOrderProvider(BasePaymentProvider):
         :param request: The HTTP request
         :param order: The order object
         """
-        order.mark_refunded()
+        from pretix.base.services.orders import mark_order_refunded
+
+        mark_order_refunded(order, user=request.user)
         messages.success(request, _('The order has been marked as refunded.'))
 
     def is_allowed(self, request: HttpRequest) -> bool:
diff --git a/src/pretix/base/services/orders.py b/src/pretix/base/services/orders.py
index 12abd79cde..33b6ebba9b 100644
--- a/src/pretix/base/services/orders.py
+++ b/src/pretix/base/services/orders.py
@@ -7,7 +7,7 @@ from django.utils.translation import ugettext_lazy as _
 from typing import List
 
 from pretix.base.models import (
-    CartPosition, Event, EventLock, Order, OrderPosition, Quota,
+    CartPosition, Event, EventLock, Order, OrderPosition, Quota, User,
 )
 from pretix.base.payment import BasePaymentProvider
 from pretix.base.services.mail import mail
@@ -31,7 +31,7 @@ error_messages = {
 
 
 def mark_order_paid(order: Order, provider: str=None, info: str=None, date: datetime=None, manual: bool=None,
-                    force: bool=False) -> Order:
+                    force: bool=False, user: User=None) -> Order:
     """
     Marks an order as paid. This sets the payment provider, info and date and returns
     the order object.
@@ -46,6 +46,7 @@ def mark_order_paid(order: Order, provider: str=None, info: str=None, date: date
     :param force: Whether this payment should be marked as paid even if no remaining
                   quota is available (default: ``False``).
     :type force: boolean
+    :param user: The user that performed the change
     :raises Quota.QuotaExceededException: if the quota is exceeded and ``force`` is ``False``
     """
     with order.event.lock():
@@ -59,6 +60,13 @@ def mark_order_paid(order: Order, provider: str=None, info: str=None, date: date
             order.payment_manual = manual
         order.status = Order.STATUS_PAID
         order.save()
+        order.log_action('pretix.event.order.paid', {
+            'provider': provider,
+            'info': info,
+            'date': date,
+            'manual': manual,
+            'force': force
+        }, user=user)
         order_paid.send(order.event, order=order)
 
     mail(
@@ -78,6 +86,32 @@ def mark_order_paid(order: Order, provider: str=None, info: str=None, date: date
     return order
 
 
+@transaction.atomic
+def mark_order_refunded(order: Order, user: User=None):
+    """
+    Mark this order as refunded. This sets the payment status and returns the order object.
+    :param order: The order to change
+    :param user: The user that performed the change
+    """
+    order.status = Order.STATUS_REFUNDED
+    order.save()
+    order.log_action('pretix.event.order.refunded', user=user)
+    return order
+
+
+@transaction.atomic
+def cancel_order(order: Order, user: User=None):
+    """
+    Mark this order as canceled
+    :param order: The order to change
+    :param user: The user that performed the change
+    """
+    order.status = Order.STATUS_CANCELLED
+    order.save()
+    order.log_action('pretix.event.order.cancelled', user=user)
+    return order
+
+
 class OrderError(Exception):
     pass
 
@@ -154,6 +188,7 @@ def _create_order(event: Event, email: str, positions: List[CartPosition], dt: d
         payment_provider=payment_provider.identifier
     )
     OrderPosition.transform_cart_positions(positions, order)
+    order.log_action('pretix.event.order.placed')
     order_placed.send(event, order=order)
     return order
 
diff --git a/src/pretix/base/settings.py b/src/pretix/base/settings.py
index 83f4299166..63d7722ae5 100644
--- a/src/pretix/base/settings.py
+++ b/src/pretix/base/settings.py
@@ -121,7 +121,20 @@ class SettingsProxy:
     def _flush(self) -> None:
         self._cached_obj = None
 
+    def freeze(self):
+        settings = {}
+        for key, v in DEFAULTS.items():
+            settings[key] = self._unserialize(v['default'], v['type'])
+        if self._parent:
+            settings.update(self._parent.settings.freeze())
+        for key, value in self._cache().items():
+            settings[key] = self.get(key)
+        return settings
+
     def _unserialize(self, value: str, as_type: type) -> Any:
+        if as_type is None and value is not None and value.startswith('file://'):
+            as_type = File
+
         if as_type is not None and isinstance(value, as_type):
             return value
         elif value is None:
@@ -186,15 +199,14 @@ class SettingsProxy:
             if value is None and default is not None:
                 value = default
 
-        if as_type is None and value is not None and value.startswith('file://'):
-            as_type = File
-
         return self._unserialize(value, as_type)
 
     def __getitem__(self, key: str) -> Any:
         return self.get(key)
 
     def __getattr__(self, key: str) -> Any:
+        if key.startswith('_'):
+            return super().__getattr__(key)
         return self.get(key)
 
     def __setattr__(self, key: str, value: Any) -> None:
diff --git a/src/pretix/control/views/auth.py b/src/pretix/control/views/auth.py
index be74cc989a..27b67e3ccc 100644
--- a/src/pretix/control/views/auth.py
+++ b/src/pretix/control/views/auth.py
@@ -62,6 +62,7 @@ def register(request):
                 timezone=request.timezone if hasattr(request, 'timezone') else settings.TIME_ZONE
             )
             user = authenticate(email=user.email, password=form.cleaned_data['password'])
+            user.log_action('pretix.control.auth.user.created', user=user)
             auth_login(request, user)
             return redirect('control:index')
     else:
@@ -90,6 +91,7 @@ class Forgot(TemplateView):
                 },
                 None, locale=user.locale
             )
+            user.log_action('pretix.control.auth.user.forgot_password.mail_sent')
             messages.success(request, _('We sent you an e-mail containing further instructions.'))
             return redirect('control:auth.forgot')
         else:
@@ -141,6 +143,7 @@ class Recover(TemplateView):
             user.set_password(self.form.cleaned_data['password'])
             user.save()
             messages.success(request, _('You can now login using your new password.'))
+            user.log_action('pretix.control.auth.user.forgot_password.recovered')
             return redirect('control:auth.login')
         else:
             return self.get(request, *args, **kwargs)
diff --git a/src/pretix/control/views/event.py b/src/pretix/control/views/event.py
index bce61f3fe0..c5f82039f8 100644
--- a/src/pretix/control/views/event.py
+++ b/src/pretix/control/views/event.py
@@ -3,6 +3,7 @@ from collections import OrderedDict
 from django import forms
 from django.contrib import messages
 from django.core.urlresolvers import reverse
+from django.db import transaction
 from django.db.models import Sum
 from django.forms import modelformset_factory
 from django.shortcuts import redirect, render
@@ -53,8 +54,17 @@ class EventUpdate(EventPermissionRequiredMixin, UpdateView):
         context['sform'] = self.sform
         return context
 
+    @transaction.atomic()
     def form_valid(self, form):
         self.sform.save()
+        if self.sform.has_changed():
+            self.request.event.log_action('pretix.event.settings', user=self.request.user, data={
+                k: self.request.event.settings.get(k) for k in self.sform.changed_data
+            })
+        if form.has_changed():
+            self.request.event.log_action('pretix.event.changed', user=self.request.user, data={
+                k: getattr(self.request.event, k) for k in form.changed_data
+            })
         messages.success(self.request, _('Your changes have been saved.'))
         return super().form_valid(form)
 
@@ -97,15 +107,20 @@ class EventPlugins(EventPermissionRequiredMixin, TemplateView, SingleObjectMixin
     def post(self, request, *args, **kwargs):
         self.object = self.get_object()
         plugins_active = self.object.get_plugins()
-        for key, value in request.POST.items():
-            if key.startswith("plugin:"):
-                module = key.split(":")[1]
-                if value == "enable":
-                    plugins_active.append(module)
-                else:
-                    plugins_active.remove(module)
-        self.object.plugins = ",".join(plugins_active)
-        self.object.save()
+        with transaction.atomic():
+            for key, value in request.POST.items():
+                if key.startswith("plugin:"):
+                    module = key.split(":")[1]
+                    if value == "enable":
+                        self.request.event.log_action('pretix.event.plugins.enabled', user=self.request.user,
+                                                      data={'plugin': module})
+                        plugins_active.append(module)
+                    else:
+                        self.request.event.log_action('pretix.event.plugins.disabled', user=self.request.user,
+                                                      data={'plugin': module})
+                        plugins_active.remove(module)
+            self.object.plugins = ",".join(plugins_active)
+            self.object.save()
         messages.success(self.request, _('Your changes have been saved.'))
         return redirect(self.get_success_url())
 
@@ -159,11 +174,18 @@ class PaymentSettings(EventPermissionRequiredMixin, TemplateView, SingleObjectMi
         context['providers'] = self.provider_forms
         return self.render_to_response(context)
 
+    @transaction.atomic()
     def post(self, request, *args, **kwargs):
         self.object = self.get_object()
         success = True
         for provider in self.provider_forms:
             if provider.form.is_valid():
+                if provider.form.has_changed():
+                    self.request.event.log_action(
+                        'pretix.event.payment.provider.' + provider.identifier, user=self.request.user, data={
+                            k: provider.form.cleaned_data.get(k) for k in provider.form.changed_data
+                        }
+                    )
                 provider.form.save()
             else:
                 success = False
@@ -207,16 +229,29 @@ class TicketSettings(EventPermissionRequiredMixin, FormView):
         form.prepare_fields()
         return form
 
+    @transaction.atomic()
     def post(self, request, *args, **kwargs):
         success = True
         for provider in self.provider_forms:
             if provider.form.is_valid():
                 provider.form.save()
+                if provider.form.has_changed():
+                    self.request.event.log_action(
+                        'pretix.event.tickets.provider.' + provider.identifier, user=self.request.user, data={
+                            k: provider.form.cleaned_data.get(k) for k in provider.form.changed_data
+                        }
+                    )
             else:
                 success = False
         form = self.get_form(self.get_form_class())
         if success and form.is_valid():
             form.save()
+            if form.has_changed():
+                self.request.event.log_action(
+                    'pretix.event.tickets.settings', user=self.request.user, data={
+                        k: form.cleaned_data.get(k) for k in form.changed_data
+                    }
+                )
             messages.success(self.request, _('Your changes have been saved.'))
             return redirect(self.get_success_url())
         else:
@@ -310,6 +345,7 @@ class EventPermissions(EventPermissionRequiredMixin, TemplateView):
         ctx['add_form'] = self.add_form
         return ctx
 
+    @transaction.atomic()
     def post(self, *args, **kwargs):
         if self.formset.is_valid() and self.add_form.is_valid():
             if self.add_form.has_changed():
@@ -327,7 +363,22 @@ class EventPermissions(EventPermissionRequiredMixin, TemplateView):
                         messages.error(self.request, _('This user already has permissions for this event.'))
                         return self.get(*args, **kwargs)
                     self.add_form.save()
+                    logdata = {
+                        k: v for k, v in self.add_form.cleaned_data.items()
+                    }
+                    logdata['user'] = self.add_form.instance.user_id
+                    self.request.event.log_action(
+                        'pretix.event.permissions.added', user=self.request.user, data=logdata
+                    )
             for form in self.formset.forms:
+                if form.has_changed():
+                    changedata = {
+                        k: form.cleaned_data.get(k) for k in form.changed_data
+                    }
+                    changedata['user'] = form.instance.user_id
+                    self.request.event.log_action(
+                        'pretix.event.permissions.changed', user=self.request.user, data=changedata
+                    )
                 if form.instance.user_id == self.request.user.pk:
                     if not form.cleaned_data['can_change_permissions'] or form in self.formset.deleted_forms:
                         messages.error(self.request, _('You cannot remove your own permission to view this page.'))
diff --git a/src/pretix/control/views/item.py b/src/pretix/control/views/item.py
index a83f8dbb52..b2eb09c144 100644
--- a/src/pretix/control/views/item.py
+++ b/src/pretix/control/views/item.py
@@ -103,12 +103,14 @@ class CategoryDelete(EventPermissionRequiredMixin, DeleteView):
         except ItemCategory.DoesNotExist:
             raise Http404(_("The requested product category does not exist."))
 
+    @transaction.atomic()
     def delete(self, request, *args, **kwargs):
         self.object = self.get_object()
         for item in self.object.items.all():
             item.category = None
             item.save()
         success_url = self.get_success_url()
+        self.object.log_action('pretix.event.category.deleted', user=self.request.user)
         self.object.delete()
         messages.success(request, _('The selected category has been deleted.'))
         return HttpResponseRedirect(success_url)
@@ -136,8 +138,15 @@ class CategoryUpdate(EventPermissionRequiredMixin, UpdateView):
         except ItemCategory.DoesNotExist:
             raise Http404(_("The requested product category does not exist."))
 
+    @transaction.atomic()
     def form_valid(self, form):
         messages.success(self.request, _('Your changes have been saved.'))
+        if form.has_changed():
+            self.object.log_action(
+                'pretix.event.category.changed', user=self.request.user, data={
+                    k: form.cleaned_data.get(k) for k in form.changed_data
+                }
+            )
         return super().form_valid(form)
 
     def get_success_url(self) -> str:
@@ -160,10 +169,13 @@ class CategoryCreate(EventPermissionRequiredMixin, CreateView):
             'event': self.request.event.slug,
         })
 
+    @transaction.atomic()
     def form_valid(self, form):
         form.instance.event = self.request.event
         messages.success(self.request, _('The new category has been created.'))
-        return super().form_valid(form)
+        ret = super().form_valid(form)
+        form.instance.log_action('pretix.event.category.added', data=dict(form.cleaned_data), user=self.request.user)
+        return ret
 
 
 class CategoryList(ListView):
@@ -248,9 +260,11 @@ class QuestionDelete(EventPermissionRequiredMixin, DeleteView):
         context['dependent'] = list(self.get_object().items.all())
         return context
 
+    @transaction.atomic()
     def delete(self, request, *args, **kwargs):
         self.object = self.get_object()
         success_url = self.get_success_url()
+        self.object.log_action(action='pretix.event.question.deleted', user=request.user)
         self.object.delete()
         messages.success(request, _('The selected question has been deleted.'))
         return HttpResponseRedirect(success_url)
@@ -277,7 +291,14 @@ class QuestionUpdate(EventPermissionRequiredMixin, UpdateView):
         except Question.DoesNotExist:
             raise Http404(_("The requested question does not exist."))
 
+    @transaction.atomic()
     def form_valid(self, form):
+        if form.has_changed():
+            self.object.log_action(
+                'pretix.event.question.changed', user=self.request.user, data={
+                    k: form.cleaned_data.get(k) for k in form.changed_data
+                }
+            )
         messages.success(self.request, _('Your changes have been saved.'))
         return super().form_valid(form)
 
@@ -306,9 +327,12 @@ class QuestionCreate(EventPermissionRequiredMixin, CreateView):
             'event': self.request.event.slug,
         })
 
+    @transaction.atomic()
     def form_valid(self, form):
         messages.success(self.request, _('The new question has been created.'))
-        return super().form_valid(form)
+        ret = super().form_valid(form)
+        form.instance.log_action('pretix.event.question.added', user=self.request.user, data=dict(form.cleaned_data))
+        return ret
 
 
 class QuotaList(ListView):
@@ -378,10 +402,13 @@ class QuotaCreate(EventPermissionRequiredMixin, QuotaEditorMixin, CreateView):
             'event': self.request.event.slug,
         })
 
+    @transaction.atomic()
     def form_valid(self, form):
         form.instance.event = self.request.event
         messages.success(self.request, _('The new quota has been created.'))
-        return super().form_valid(form)
+        ret = super().form_valid(form)
+        form.instance.log_action('pretix.event.quota.added', user=self.request.user, data=dict(form.cleaned_data))
+        return ret
 
 
 class QuotaUpdate(EventPermissionRequiredMixin, QuotaEditorMixin, UpdateView):
@@ -399,8 +426,15 @@ class QuotaUpdate(EventPermissionRequiredMixin, QuotaEditorMixin, UpdateView):
         except Quota.DoesNotExist:
             raise Http404(_("The requested quota does not exist."))
 
+    @transaction.atomic()
     def form_valid(self, form):
         messages.success(self.request, _('Your changes have been saved.'))
+        if form.has_changed():
+            self.object.log_action(
+                'pretix.event.quota.changed', user=self.request.user, data={
+                    k: form.cleaned_data.get(k) for k in form.changed_data
+                }
+            )
         return super().form_valid(form)
 
     def get_success_url(self) -> str:
@@ -429,9 +463,11 @@ class QuotaDelete(EventPermissionRequiredMixin, DeleteView):
         context['dependent'] = list(self.get_object().items.all())
         return context
 
+    @transaction.atomic()
     def delete(self, request, *args, **kwargs):
         self.object = self.get_object()
         success_url = self.get_success_url()
+        self.object.log_action(action='pretix.event.quota.deleted', user=request.user)
         self.object.delete()
         messages.success(self.request, _('The selected quota has been deleted.'))
         return HttpResponseRedirect(success_url)
@@ -471,9 +507,12 @@ class ItemCreate(EventPermissionRequiredMixin, CreateView):
             'item': self.object.id,
         })
 
+    @transaction.atomic()
     def form_valid(self, form):
         messages.success(self.request, _('Your changes have been saved.'))
-        return super().form_valid(form)
+        ret = super().form_valid(form)
+        form.instance.log_action('pretix.event.item.added', user=self.request.user, data=dict(form.cleaned_data))
+        return ret
 
     def get_form_kwargs(self):
         """
@@ -497,8 +536,15 @@ class ItemUpdateGeneral(ItemDetailMixin, EventPermissionRequiredMixin, UpdateVie
             'item': self.get_object().id,
         })
 
+    @transaction.atomic()
     def form_valid(self, form):
         messages.success(self.request, _('Your changes have been saved.'))
+        if form.has_changed():
+            self.object.log_action(
+                'pretix.event.item.changed', user=self.request.user, data={
+                    k: form.cleaned_data.get(k) for k in form.changed_data
+                }
+            )
         return super().form_valid(form)
 
 
@@ -543,13 +589,31 @@ class ItemProperties(ItemDetailMixin, EventPermissionRequiredMixin, TemplateView
         for f in formset:
             f.instance.event = self.request.event
             f.instance.item = self.get_object()
+            is_created = not f.instance.pk
             f.instance.save()
-            print(f.instance)
+            if f.has_changed() and not is_created:
+                change_data = {
+                    k: f.cleaned_data.get(k) for k in f.changed_data
+                }
+                change_data['id'] = f.instance.pk
+                f.instance.item.log_action(
+                    'pretix.event.item.property.changed', user=self.request.user, data=change_data
+                )
+            elif is_created:
+                change_data = dict(f.cleaned_data)
+                change_data['id'] = f.instance.pk
+                f.instance.item.log_action(
+                    'pretix.event.item.property.added', user=self.request.user, data=change_data
+                )
 
             for n in f.nested:
-                print(n.deleted_forms, n.ordered_forms, n.extra_forms)
 
                 for fn in n.deleted_forms:
+                    f.instance.item.log_action(
+                        'pretix.event.item.property.value.deleted', user=self.request.user, data={
+                            'id': fn.instance.pk
+                        }
+                    )
                     fn.instance.delete()
                     fn.instance.pk = None
 
@@ -557,8 +621,24 @@ class ItemProperties(ItemDetailMixin, EventPermissionRequiredMixin, TemplateView
                     fn.instance.position = i
                     fn.instance.prop = f.instance
                     fn.save()
+                    if f.has_changed():
+                        change_data = {k: f.cleaned_data.get(k) for k in f.changed_data}
+                        change_data['id'] = f.instance.pk
+                        f.instance.item.log_action(
+                            'pretix.event.item.property.value.changed', user=self.request.user, data=change_data
+                        )
 
-                n.save_new_objects()
+                for form in n.extra_forms:
+                    if not form.has_changed():
+                        continue
+                    if n.can_delete and n._should_delete_form(form):
+                        continue
+                    change_data = dict(f.cleaned_data)
+                    n.save_new(form)
+                    change_data['id'] = form.instance.pk
+                    f.instance.item.log_action(
+                        'pretix.event.item.property.value.added', user=self.request.user, data=change_data
+                    )
         messages.success(self.request, _('Your changes have been saved.'))
         return redirect(self.get_success_url())
 
@@ -700,6 +780,13 @@ class ItemVariations(ItemDetailMixin, EventPermissionRequiredMixin, TemplateView
             for form in self.forms_flat:
                 if form.is_valid() and form.has_changed():
                     form.save()
+                    change_data = {
+                        k: form.cleaned_data.get(k) for k in form.changed_data
+                    }
+                    change_data['id'] = form.instance.pk
+                    self.object.log_action(
+                        'pretix.event.item.variation.changed', user=self.request.user, data=change_data
+                    )
                     if hasattr(form.instance, 'creation') and form.instance.creation:
                         # We need this special 'creation' field set to true in get_form
                         # for newly created items as cleanerversion does already set the
@@ -758,9 +845,11 @@ class ItemDelete(EventPermissionRequiredMixin, DeleteView):
                 raise Http404(_("The requested product does not exist."))
         return self.object
 
+    @transaction.atomic
     def delete(self, request, *args, **kwargs):
         success_url = self.get_success_url()
         if self.is_allowed():
+            self.get_object().log_action('pretix.event.item.deleted', user=self.request.user)
             self.get_object().delete()
             messages.success(request, _('The selected product has been deleted.'))
             return HttpResponseRedirect(success_url)
@@ -768,6 +857,9 @@ class ItemDelete(EventPermissionRequiredMixin, DeleteView):
             o = self.get_object()
             o.active = False
             o.save()
+            o.log_action('pretix.event.item.changed', user=self.request.user, data={
+                'active': False
+            })
             messages.success(request, _('The selected product has been deactivated.'))
             return HttpResponseRedirect(success_url)
 
diff --git a/src/pretix/control/views/orders.py b/src/pretix/control/views/orders.py
index d108422906..9d782cc146 100644
--- a/src/pretix/control/views/orders.py
+++ b/src/pretix/control/views/orders.py
@@ -17,7 +17,7 @@ from pretix.base.models import (
 )
 from pretix.base.services import tickets
 from pretix.base.services.export import export
-from pretix.base.services.orders import mark_order_paid
+from pretix.base.services.orders import cancel_order, mark_order_paid
 from pretix.base.services.stats import order_overview
 from pretix.base.signals import (
     register_data_exporters, register_payment_providers,
@@ -136,8 +136,8 @@ class OrderDetail(OrderView):
         def keyfunc(pos):
             if (pos.item.admission and self.request.event.settings.attendee_names_asked) \
                     or pos.item.questions.all():
-                return pos.id, "", "", ""
-            return "", pos.item_id, pos.variation_id, pos.price
+                return pos.id, 0, 0, 0
+            return 0, pos.item_id, pos.variation_id, pos.price
 
         positions = []
         for k, g in groupby(sorted(list(cartpos), key=keyfunc), key=keyfunc):
@@ -164,19 +164,19 @@ class OrderTransition(OrderView):
         to = self.request.POST.get('status', '')
         if self.order.status == 'n' and to == 'p':
             try:
-                mark_order_paid(self.order, manual=True)
+                mark_order_paid(self.order, manual=True, user=self.request.user)
             except Quota.QuotaExceededException as e:
                 messages.error(self.request, str(e))
             else:
                 messages.success(self.request, _('The order has been marked as paid.'))
         elif self.order.status == 'n' and to == 'c':
-            self.order.status = Order.STATUS_CANCELLED
-            self.order.save()
+            cancel_order(self.order, user=self.request.user)
             messages.success(self.request, _('The order has been cancelled.'))
         elif self.order.status == 'p' and to == 'n':
             self.order.status = Order.STATUS_PENDING
             self.order.payment_manual = True
             self.order.save()
+            self.order.log_action('pretix.base.order.unpaid', user=self.request.user)
             messages.success(self.request, _('The order has been marked as not paid.'))
         elif self.order.status == 'p' and to == 'r':
             ret = self.payment_provider.order_control_refund_perform(self.request, self.order)
@@ -247,6 +247,9 @@ class OrderExtend(OrderView):
         if self.form.is_valid():
             if oldvalue > now():
                 messages.success(self.request, _('The payment term has been changed.'))
+                self.order.log_action('pretix.order.changed', user=self.request.user, data={
+                    'expires': self.order.expires
+                })
                 self.form.save()
             else:
                 try:
@@ -254,6 +257,9 @@ class OrderExtend(OrderView):
                         is_available = self.order._is_still_available()
                         if is_available is True:
                             self.form.save()
+                            self.order.log_action('pretix.order.changed', user=self.request.user, data={
+                                'expires': self.order.expires
+                            })
                             messages.success(self.request, _('The payment term has been changed.'))
                         else:
                             messages.error(self.request, is_available)
diff --git a/src/pretix/plugins/paypal/payment.py b/src/pretix/plugins/paypal/payment.py
index e466188125..805e965e91 100644
--- a/src/pretix/plugins/paypal/payment.py
+++ b/src/pretix/plugins/paypal/payment.py
@@ -10,7 +10,7 @@ from django.utils.translation import ugettext as __, ugettext_lazy as _
 
 from pretix.base.models import Quota
 from pretix.base.payment import BasePaymentProvider
-from pretix.base.services.orders import mark_order_paid
+from pretix.base.services.orders import mark_order_paid, mark_order_refunded
 from pretix.multidomain.urlreverse import build_absolute_uri
 
 logger = logging.getLogger('pretix.plugins.paypal')
@@ -218,7 +218,7 @@ class Paypal(BasePaymentProvider):
             payment_info = None
 
         if not payment_info:
-            order.mark_refunded()
+            mark_order_refunded(order)
             messages.warning(request, _('We were unable to transfer the money back automatically. '
                                         'Please get in touch with the customer and transfer it back manually.'))
             return
@@ -231,11 +231,11 @@ class Paypal(BasePaymentProvider):
 
         refund = sale.refund({})
         if not refund.success():
-            order.mark_refunded()
+            mark_order_refunded(order, user=request.user)
             messages.warning(request, _('We were unable to transfer the money back automatically. '
                                         'Please get in touch with the customer and transfer it back manually.'))
         else:
             sale = paypalrestsdk.Payment.find(payment_info['id'])
-            order = order.mark_refunded()
+            order = mark_order_refunded(order)
             order.payment_info = json.dumps(sale.to_dict())
             order.save()
diff --git a/src/pretix/plugins/sendmail/views.py b/src/pretix/plugins/sendmail/views.py
index a33a94ad08..72e5ec282f 100644
--- a/src/pretix/plugins/sendmail/views.py
+++ b/src/pretix/plugins/sendmail/views.py
@@ -27,12 +27,15 @@ class SenderView(EventPermissionRequiredMixin, FormView):
     def form_valid(self, form):
         orders = Order.objects.filter(
             event=self.request.event, status__in=form.cleaned_data['sendto']
-        ).select_related("user")
-        users = set([o.user for o in orders])
+        )
+        mails = set([o.email for o in orders])
 
-        for u in users:
-            mail(u.email, form.cleaned_data['subject'], form.cleaned_data['message'],
-                 None, self.request.event, locale=u.locale)
+        self.request.event.log_action('pretix.plugins.sendmail.sent', user=self.request.user, data=dict(
+            form.cleaned_data))
+
+        for m in mails:
+            mail(m, form.cleaned_data['subject'], form.cleaned_data['message'],
+                 None, self.request.event, locale=m.locale)
 
         messages.success(self.request, _('Your message will be sent to the selected users.'))
 
diff --git a/src/pretix/plugins/stripe/payment.py b/src/pretix/plugins/stripe/payment.py
index 6fbe062c46..e16869f0d8 100644
--- a/src/pretix/plugins/stripe/payment.py
+++ b/src/pretix/plugins/stripe/payment.py
@@ -10,7 +10,7 @@ from django.utils.translation import ugettext_lazy as _
 
 from pretix.base.models import Quota
 from pretix.base.payment import BasePaymentProvider
-from pretix.base.services.orders import mark_order_paid
+from pretix.base.services.orders import mark_order_paid, mark_order_refunded
 from pretix.helpers.urls import build_absolute_uri
 
 logger = logging.getLogger('pretix.plugins.stripe')
@@ -157,7 +157,7 @@ class Stripe(BasePaymentProvider):
             payment_info = None
 
         if not payment_info:
-            order.mark_refunded()
+            mark_order_refunded(order, user=request.user)
             messages.warning(request, _('We were unable to transfer the money back automatically. '
                                         'Please get in touch with the customer and transfer it back manually.'))
             return
@@ -173,10 +173,10 @@ class Stripe(BasePaymentProvider):
                                       'support if the problem persists.'))
             logger.error('Stripe error: %s' % str(err))
         except stripe.error.StripeError:
-            order.mark_refunded()
+            mark_order_refunded(order)
             messages.warning(request, _('We were unable to transfer the money back automatically. '
                                         'Please get in touch with the customer and transfer it back manually.'))
         else:
-            order = order.mark_refunded()
+            order = mark_order_refunded(order)
             order.payment_info = str(ch)
             order.save()
diff --git a/src/pretix/plugins/stripe/views.py b/src/pretix/plugins/stripe/views.py
index 42bfc200c9..bcaf6a9e06 100644
--- a/src/pretix/plugins/stripe/views.py
+++ b/src/pretix/plugins/stripe/views.py
@@ -7,6 +7,7 @@ from django.views.decorators.csrf import csrf_exempt
 from django.views.decorators.http import require_POST
 
 from pretix.base.models import Event, Order
+from pretix.base.services.orders import mark_order_refunded
 from pretix.plugins.stripe.payment import Stripe
 
 logger = logging.getLogger('pretix.plugins.stripe')
@@ -42,6 +43,8 @@ def webhook(request):
     prov = Stripe(event)
     prov._init_api()
 
+    order.log_action('pretix.plugins.stripe.event', data=event_json)
+
     try:
         charge = stripe.Charge.retrieve(charge['id'])
     except stripe.error.StripeError as err:
@@ -49,6 +52,6 @@ def webhook(request):
         return HttpResponse('StripeError', status=500)
 
     if charge['refunds']['total_count'] > 0 and order.status == Order.STATUS_PAID:
-        order.mark_refunded()
+        mark_order_refunded(order)
 
     return HttpResponse(status=200)
diff --git a/src/pretix/presale/views/order.py b/src/pretix/presale/views/order.py
index ed8b796ea3..d0aad2b795 100644
--- a/src/pretix/presale/views/order.py
+++ b/src/pretix/presale/views/order.py
@@ -10,6 +10,7 @@ from django.utils.translation import ugettext_lazy as _
 from django.views.generic import TemplateView, View
 
 from pretix.base.models import CachedFile, CachedTicket, Order, OrderPosition
+from pretix.base.services.orders import cancel_order
 from pretix.base.services.tickets import generate
 from pretix.base.signals import (
     register_payment_providers, register_ticket_outputs,
@@ -215,6 +216,7 @@ class OrderModify(EventViewMixin, OrderDetailMixin, QuestionsViewMixin, Template
             messages.error(self.request,
                            _("We had difficulties processing your input. Please review the errors below."))
             return self.get(request, *args, **kwargs)
+        self.order.log_action('pretix.event.order.modified')
         return redirect(self.get_order_url())
 
     def get(self, request, *args, **kwargs):
@@ -251,8 +253,7 @@ class OrderCancel(EventViewMixin, OrderDetailMixin, TemplateView):
         return super().dispatch(request, *args, **kwargs)
 
     def post(self, request, *args, **kwargs):
-        self.order.status = Order.STATUS_CANCELLED
-        self.order.save()
+        cancel_order(self.order)
         return redirect(self.get_order_url())
 
     def get(self, request, *args, **kwargs):
diff --git a/src/tests/base/test_settings.py b/src/tests/base/test_settings.py
index 8249559b2e..6f7defeeda 100644
--- a/src/tests/base/test_settings.py
+++ b/src/tests/base/test_settings.py
@@ -12,7 +12,6 @@ from pretix.base.settings import SettingsSandbox
 
 
 class SettingsTestCase(TestCase):
-
     def setUp(self):
         settings.DEFAULTS['test_default'] = {
             'default': 'def',
@@ -149,6 +148,7 @@ class SettingsTestCase(TestCase):
     def test_serialize_unknown(self):
         class Type:
             pass
+
         try:
             self._test_serialization(Type(), Type)
             self.assertTrue(False, 'No exception thrown!')
@@ -195,3 +195,23 @@ class SettingsTestCase(TestCase):
 
         self.assertIsNone(sandbox.bar)
         self.assertIsNone(sandbox['baz'])
+
+    def test_freeze(self):
+        olddef = settings.DEFAULTS
+        settings.DEFAULTS = {
+            'test_default': {
+                'default': 'def',
+                'type': str
+            }
+        }
+        self.event.organizer.settings.set('bar', 'baz')
+        self.event.organizer.settings.set('foo', 'baz')
+        self.event.settings.set('foo', 'bar')
+        try:
+            self.assertEqual(self.event.settings.freeze(), {
+                'test_default': 'def',
+                'bar': 'baz',
+                'foo': 'bar'
+            })
+        finally:
+            settings.DEFAULTS = olddef