diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 48548f8c4..9989b7659 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -154,7 +154,8 @@ def serialize_event(e, time_now_ms, as_client_event=True,
 
     if "redacted_because" in e.unsigned:
         d["unsigned"]["redacted_because"] = serialize_event(
-            e.unsigned["redacted_because"], time_now_ms
+            e.unsigned["redacted_because"], time_now_ms,
+            event_format=event_format
         )
 
     if token_id is not None:
diff --git a/synapse/handlers/__init__.py b/synapse/handlers/__init__.py
index 87b4d381c..6a2339f2e 100644
--- a/synapse/handlers/__init__.py
+++ b/synapse/handlers/__init__.py
@@ -17,7 +17,7 @@ from synapse.appservice.scheduler import AppServiceScheduler
 from synapse.appservice.api import ApplicationServiceApi
 from .register import RegistrationHandler
 from .room import (
-    RoomCreationHandler, RoomMemberHandler, RoomListHandler
+    RoomCreationHandler, RoomMemberHandler, RoomListHandler, RoomContextHandler,
 )
 from .message import MessageHandler
 from .events import EventStreamHandler, EventHandler
@@ -70,3 +70,4 @@ class Handlers(object):
         self.auth_handler = AuthHandler(hs)
         self.identity_handler = IdentityHandler(hs)
         self.search_handler = SearchHandler(hs)
+        self.room_context_handler = RoomContextHandler(hs)
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 60f9fa58b..36878a6c2 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -33,6 +33,7 @@ from collections import OrderedDict
 from unpaddedbase64 import decode_base64
 
 import logging
+import math
 import string
 
 logger = logging.getLogger(__name__)
@@ -747,6 +748,60 @@ class RoomListHandler(BaseHandler):
         defer.returnValue({"start": "START", "end": "END", "chunk": chunk})
 
 
+class RoomContextHandler(BaseHandler):
+    @defer.inlineCallbacks
+    def get_event_context(self, user, room_id, event_id, limit):
+        """Retrieves events, pagination tokens and state around a given event
+        in a room.
+
+        Args:
+            user (UserID)
+            room_id (str)
+            event_id (str)
+            limit (int): The maximum number of events to return in total
+                (excluding state).
+
+        Returns:
+            dict
+        """
+        before_limit = math.floor(limit/2.)
+        after_limit = limit - before_limit
+
+        now_token = yield self.hs.get_event_sources().get_current_token()
+
+        results = yield self.store.get_events_around(
+            room_id, event_id, before_limit, after_limit
+        )
+
+        results["events_before"] = yield self._filter_events_for_client(
+            user.to_string(), results["events_before"]
+        )
+
+        results["events_after"] = yield self._filter_events_for_client(
+            user.to_string(), results["events_after"]
+        )
+
+        if results["events_after"]:
+            last_event_id = results["events_after"][-1].event_id
+        else:
+            last_event_id = event_id
+
+        state = yield self.store.get_state_for_events(
+            [last_event_id], None
+        )
+        results["state"] = state[last_event_id].values()
+
+        results["start"] = now_token.copy_and_replace(
+            "room_key", results["start"]
+        ).to_string()
+
+        results["end"] = now_token.copy_and_replace(
+            "room_key", results["end"]
+        ).to_string()
+
+        defer.returnValue(results)
+
+
 class RoomEventSource(object):
     def __init__(self, hs):
         self.store = hs.get_datastore()
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index bbe82b142..2718e9482 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -51,6 +51,17 @@ class SearchHandler(BaseHandler):
                 "content.body", "content.name", "content.topic",
             ])
             filter_dict = content["search_categories"]["room_events"].get("filter", {})
+            event_context = content["search_categories"]["room_events"].get(
+                "event_context", None
+            )
+
+            if event_context is not None:
+                before_limit = int(event_context.get(
+                    "before_limit", 5
+                ))
+                after_limit = int(event_context.get(
+                    "after_limit", 5
+                ))
         except KeyError:
             raise SynapseError(400, "Invalid search query")
 
@@ -76,14 +87,57 @@ class SearchHandler(BaseHandler):
             user.to_string(), filtered_events
         )
 
+        allowed_events.sort(key=lambda e: -rank_map[e.event_id])
+        allowed_events = allowed_events[:search_filter.limit()]
+
+        if event_context is not None:
+            now_token = yield self.hs.get_event_sources().get_current_token()
+
+            contexts = {}
+            for event in allowed_events:
+                res = yield self.store.get_events_around(
+                    event.room_id, event.event_id, before_limit, after_limit
+                )
+
+                res["events_before"] = yield self._filter_events_for_client(
+                    user.to_string(), res["events_before"]
+                )
+
+                res["events_after"] = yield self._filter_events_for_client(
+                    user.to_string(), res["events_after"]
+                )
+
+                res["start"] = now_token.copy_and_replace(
+                    "room_key", res["start"]
+                ).to_string()
+
+                res["end"] = now_token.copy_and_replace(
+                    "room_key", res["end"]
+                ).to_string()
+
+                contexts[event.event_id] = res
+        else:
+            contexts = {}
+
         # TODO: Add a limit
 
         time_now = self.clock.time_msec()
 
+        for context in contexts.values():
+            context["events_before"] = [
+                serialize_event(e, time_now)
+                for e in context["events_before"]
+            ]
+            context["events_after"] = [
+                serialize_event(e, time_now)
+                for e in context["events_after"]
+            ]
+
         results = {
             e.event_id: {
                 "rank": rank_map[e.event_id],
-                "result": serialize_event(e, time_now)
+                "result": serialize_event(e, time_now),
+                "context": contexts.get(e.event_id, {}),
             }
             for e in allowed_events
         }
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index b8e2c8196..4c5a2353b 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -113,15 +113,20 @@ class SyncHandler(BaseHandler):
         self.clock = hs.get_clock()
 
     @defer.inlineCallbacks
-    def wait_for_sync_for_user(self, sync_config, since_token=None, timeout=0):
+    def wait_for_sync_for_user(self, sync_config, since_token=None, timeout=0,
+                               full_state=False):
         """Get the sync for a client if we have new data for it now. Otherwise
         wait for new data to arrive on the server. If the timeout expires, then
         return an empty sync result.
         Returns:
             A Deferred SyncResult.
         """
-        if timeout == 0 or since_token is None:
-            result = yield self.current_sync_for_user(sync_config, since_token)
+
+        if timeout == 0 or since_token is None or full_state:
+            # we are going to return immediately, so don't bother calling
+            # notifier.wait_for_events.
+            result = yield self.current_sync_for_user(sync_config, since_token,
+                                                      full_state=full_state)
             defer.returnValue(result)
         else:
             def current_sync_callback(before_token, after_token):
@@ -146,19 +151,24 @@ class SyncHandler(BaseHandler):
             )
             defer.returnValue(result)
 
-    def current_sync_for_user(self, sync_config, since_token=None):
+    def current_sync_for_user(self, sync_config, since_token=None,
+                              full_state=False):
         """Get the sync for client needed to match what the server has now.
         Returns:
             A Deferred SyncResult.
         """
-        if since_token is None:
-            return self.initial_sync(sync_config)
+        if since_token is None or full_state:
+            return self.full_state_sync(sync_config, since_token)
         else:
             return self.incremental_sync_with_gap(sync_config, since_token)
 
     @defer.inlineCallbacks
-    def initial_sync(self, sync_config):
-        """Get a sync for a client which is starting without any state
+    def full_state_sync(self, sync_config, timeline_since_token):
+        """Get a sync for a client which is starting without any state.
+
+        If a 'message_since_token' is given, only timeline events which have
+        happened since that token will be returned.
+
         Returns:
             A Deferred SyncResult.
         """
@@ -192,8 +202,12 @@ class SyncHandler(BaseHandler):
         archived = []
         for event in room_list:
             if event.membership == Membership.JOIN:
-                room_sync = yield self.initial_sync_for_joined_room(
-                    event.room_id, sync_config, now_token, typing_by_room
+                room_sync = yield self.full_state_sync_for_joined_room(
+                    room_id=event.room_id,
+                    sync_config=sync_config,
+                    now_token=now_token,
+                    timeline_since_token=timeline_since_token,
+                    typing_by_room=typing_by_room
                 )
                 joined.append(room_sync)
             elif event.membership == Membership.INVITE:
@@ -206,11 +220,12 @@ class SyncHandler(BaseHandler):
                 leave_token = now_token.copy_and_replace(
                     "room_key", "s%d" % (event.stream_ordering,)
                 )
-                room_sync = yield self.initial_sync_for_archived_room(
+                room_sync = yield self.full_state_sync_for_archived_room(
                     sync_config=sync_config,
                     room_id=event.room_id,
                     leave_event_id=event.event_id,
                     leave_token=leave_token,
+                    timeline_since_token=timeline_since_token,
                 )
                 archived.append(room_sync)
 
@@ -223,15 +238,16 @@ class SyncHandler(BaseHandler):
         ))
 
     @defer.inlineCallbacks
-    def initial_sync_for_joined_room(self, room_id, sync_config, now_token,
-                                     typing_by_room):
+    def full_state_sync_for_joined_room(self, room_id, sync_config,
+                                        now_token, timeline_since_token,
+                                        typing_by_room):
         """Sync a room for a client which is starting without any state
         Returns:
             A Deferred JoinedSyncResult.
         """
 
         batch = yield self.load_filtered_recents(
-            room_id, sync_config, now_token,
+            room_id, sync_config, now_token, since_token=timeline_since_token
         )
 
         current_state = yield self.state_handler.get_current_state(
@@ -278,15 +294,16 @@ class SyncHandler(BaseHandler):
         defer.returnValue((now_token, typing_by_room))
 
     @defer.inlineCallbacks
-    def initial_sync_for_archived_room(self, room_id, sync_config,
-                                       leave_event_id, leave_token):
+    def full_state_sync_for_archived_room(self, room_id, sync_config,
+                                          leave_event_id, leave_token,
+                                          timeline_since_token):
         """Sync a room for a client which is starting without any state
         Returns:
             A Deferred JoinedSyncResult.
         """
 
         batch = yield self.load_filtered_recents(
-            room_id, sync_config, leave_token,
+            room_id, sync_config, leave_token, since_token=timeline_since_token
         )
 
         leave_state = yield self.store.get_state_for_events(
@@ -370,7 +387,7 @@ class SyncHandler(BaseHandler):
                 else:
                     prev_batch = now_token
 
-                state = yield self.check_joined_room(
+                state, limited = yield self.check_joined_room(
                     sync_config, room_id, state
                 )
 
@@ -379,7 +396,7 @@ class SyncHandler(BaseHandler):
                     timeline=TimelineBatch(
                         events=recents,
                         prev_batch=prev_batch,
-                        limited=False,
+                        limited=limited,
                     ),
                     state=state,
                     ephemeral=typing_by_room.get(room_id, [])
@@ -503,7 +520,7 @@ class SyncHandler(BaseHandler):
             current_state=current_state_events,
         )
 
-        state_events_delta = yield self.check_joined_room(
+        state_events_delta, _ = yield self.check_joined_room(
             sync_config, room_id, state_events_delta
         )
 
@@ -610,6 +627,7 @@ class SyncHandler(BaseHandler):
     @defer.inlineCallbacks
     def check_joined_room(self, sync_config, room_id, state_delta):
         joined = False
+        limited = False
         for event in state_delta:
             if (
                 event.type == EventTypes.Member
@@ -621,5 +639,6 @@ class SyncHandler(BaseHandler):
         if joined:
             res = yield self.state_handler.get_current_state(room_id)
             state_delta = res.values()
+            limited = True
 
-        defer.returnValue(state_delta)
+        defer.returnValue((state_delta, limited))
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 4cee1c159..2dcaee86c 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -397,6 +397,41 @@ class RoomTriggerBackfill(ClientV1RestServlet):
         defer.returnValue((200, res))
 
 
+class RoomEventContext(ClientV1RestServlet):
+    PATTERN = client_path_pattern(
+        "/rooms/(?P<room_id>[^/]*)/context/(?P<event_id>[^/]*)$"
+    )
+
+    def __init__(self, hs):
+        super(RoomEventContext, self).__init__(hs)
+        self.clock = hs.get_clock()
+
+    @defer.inlineCallbacks
+    def on_GET(self, request, room_id, event_id):
+        user, _ = yield self.auth.get_user_by_req(request)
+
+        limit = int(request.args.get("limit", [10])[0])
+
+        results = yield self.handlers.room_context_handler.get_event_context(
+            user, room_id, event_id, limit,
+        )
+
+        time_now = self.clock.time_msec()
+        results["events_before"] = [
+            serialize_event(event, time_now) for event in results["events_before"]
+        ]
+        results["events_after"] = [
+            serialize_event(event, time_now) for event in results["events_after"]
+        ]
+        results["state"] = [
+            serialize_event(event, time_now) for event in results["state"]
+        ]
+
+        logger.info("Responding with %r", results)
+
+        defer.returnValue((200, results))
+
+
 # TODO: Needs unit testing
 class RoomMembershipRestServlet(ClientV1RestServlet):
 
@@ -628,3 +663,4 @@ def register_servlets(hs, http_server):
     RoomRedactEventRestServlet(hs).register(http_server)
     RoomTypingRestServlet(hs).register(http_server)
     SearchRestServlet(hs).register(http_server)
+    RoomEventContext(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index 6c4f2b7cd..1840eef77 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -16,7 +16,7 @@
 from twisted.internet import defer
 
 from synapse.http.servlet import (
-    RestServlet, parse_string, parse_integer
+    RestServlet, parse_string, parse_integer, parse_boolean
 )
 from synapse.handlers.sync import SyncConfig
 from synapse.types import StreamToken
@@ -90,6 +90,7 @@ class SyncRestServlet(RestServlet):
             allowed_values=self.ALLOWED_PRESENCE
         )
         filter_id = parse_string(request, "filter", default=None)
+        full_state = parse_boolean(request, "full_state", default=False)
 
         logger.info(
             "/sync: user=%r, timeout=%r, since=%r,"
@@ -120,7 +121,8 @@ class SyncRestServlet(RestServlet):
 
         try:
             sync_result = yield self.sync_handler.wait_for_sync_for_user(
-                sync_config, since_token=since_token, timeout=timeout
+                sync_config, since_token=since_token, timeout=timeout,
+                full_state=full_state
             )
         finally:
             if set_presence == "online":
diff --git a/synapse/storage/stream.py b/synapse/storage/stream.py
index 3cab06fde..15d4c2bf6 100644
--- a/synapse/storage/stream.py
+++ b/synapse/storage/stream.py
@@ -23,7 +23,7 @@ paginate bacwards.
 
 This is implemented by keeping two ordering columns: stream_ordering and
 topological_ordering. Stream ordering is basically insertion/received order
-(except for events from backfill requests). The topolgical_ordering is a
+(except for events from backfill requests). The topological_ordering is a
 weak ordering of events based on the pdu graph.
 
 This means that we have to have two different types of tokens, depending on
@@ -436,3 +436,138 @@ class StreamStore(SQLBaseStore):
             internal = event.internal_metadata
             internal.before = str(RoomStreamToken(topo, stream - 1))
             internal.after = str(RoomStreamToken(topo, stream))
+
+    @defer.inlineCallbacks
+    def get_events_around(self, room_id, event_id, before_limit, after_limit):
+        """Retrieve events and pagination tokens around a given event in a
+        room.
+
+        Args:
+            room_id (str)
+            event_id (str)
+            before_limit (int)
+            after_limit (int)
+
+        Returns:
+            dict
+        """
+
+        results = yield self.runInteraction(
+            "get_events_around", self._get_events_around_txn,
+            room_id, event_id, before_limit, after_limit
+        )
+
+        events_before = yield self._get_events(
+            [e for e in results["before"]["event_ids"]],
+            get_prev_content=True
+        )
+
+        events_after = yield self._get_events(
+            [e for e in results["after"]["event_ids"]],
+            get_prev_content=True
+        )
+
+        defer.returnValue({
+            "events_before": events_before,
+            "events_after": events_after,
+            "start": results["before"]["token"],
+            "end": results["after"]["token"],
+        })
+
+    def _get_events_around_txn(self, txn, room_id, event_id, before_limit, after_limit):
+        """Retrieves event_ids and pagination tokens around a given event in a
+        room.
+
+        Args:
+            room_id (str)
+            event_id (str)
+            before_limit (int)
+            after_limit (int)
+
+        Returns:
+            dict
+        """
+
+        results = self._simple_select_one_txn(
+            txn,
+            "events",
+            keyvalues={
+                "event_id": event_id,
+                "room_id": room_id,
+            },
+            retcols=["stream_ordering", "topological_ordering"],
+        )
+
+        stream_ordering = results["stream_ordering"]
+        topological_ordering = results["topological_ordering"]
+
+        query_before = (
+            "SELECT topological_ordering, stream_ordering, event_id FROM events"
+            " WHERE room_id = ? AND (topological_ordering < ?"
+            " OR (topological_ordering = ? AND stream_ordering < ?))"
+            " ORDER BY topological_ordering DESC, stream_ordering DESC"
+            " LIMIT ?"
+        )
+
+        query_after = (
+            "SELECT topological_ordering, stream_ordering, event_id FROM events"
+            " WHERE room_id = ? AND (topological_ordering > ?"
+            " OR (topological_ordering = ? AND stream_ordering > ?))"
+            " ORDER BY topological_ordering ASC, stream_ordering ASC"
+            " LIMIT ?"
+        )
+
+        txn.execute(
+            query_before,
+            (
+                room_id, topological_ordering, topological_ordering,
+                stream_ordering, before_limit,
+            )
+        )
+
+        rows = self.cursor_to_dict(txn)
+        events_before = [r["event_id"] for r in rows]
+
+        if rows:
+            start_token = str(RoomStreamToken(
+                rows[0]["topological_ordering"],
+                rows[0]["stream_ordering"] - 1,
+            ))
+        else:
+            start_token = str(RoomStreamToken(
+                topological_ordering,
+                stream_ordering - 1,
+            ))
+
+        txn.execute(
+            query_after,
+            (
+                room_id, topological_ordering, topological_ordering,
+                stream_ordering, after_limit,
+            )
+        )
+
+        rows = self.cursor_to_dict(txn)
+        events_after = [r["event_id"] for r in rows]
+
+        if rows:
+            end_token = str(RoomStreamToken(
+                rows[-1]["topological_ordering"],
+                rows[-1]["stream_ordering"],
+            ))
+        else:
+            end_token = str(RoomStreamToken(
+                topological_ordering,
+                stream_ordering,
+            ))
+
+        return {
+            "before": {
+                "event_ids": events_before,
+                "token": start_token,
+            },
+            "after": {
+                "event_ids": events_after,
+                "token": end_token,
+            },
+        }
diff --git a/synapse/types.py b/synapse/types.py
index 84631d177..28344d8b3 100644
--- a/synapse/types.py
+++ b/synapse/types.py
@@ -47,7 +47,7 @@ class DomainSpecificString(
     @classmethod
     def from_string(cls, s):
         """Parse the string given by 's' into a structure object."""
-        if s[0] != cls.SIGIL:
+        if len(s) < 1 or s[0] != cls.SIGIL:
             raise SynapseError(400, "Expected %s string to start with '%s'" % (
                 cls.__name__, cls.SIGIL,
             ))
diff --git a/tests/test_types.py b/tests/test_types.py
index b29a8415b..495cd20f0 100644
--- a/tests/test_types.py
+++ b/tests/test_types.py
@@ -15,13 +15,14 @@
 
 from tests import unittest
 
+from synapse.api.errors import SynapseError
 from synapse.server import BaseHomeServer
 from synapse.types import UserID, RoomAlias
 
 mock_homeserver = BaseHomeServer(hostname="my.domain")
 
-class UserIDTestCase(unittest.TestCase):
 
+class UserIDTestCase(unittest.TestCase):
     def test_parse(self):
         user = UserID.from_string("@1234abcd:my.domain")
 
@@ -29,6 +30,11 @@ class UserIDTestCase(unittest.TestCase):
         self.assertEquals("my.domain", user.domain)
         self.assertEquals(True, mock_homeserver.is_mine(user))
 
+    def test_pase_empty(self):
+        with self.assertRaises(SynapseError):
+            UserID.from_string("")
+
+
     def test_build(self):
         user = UserID("5678efgh", "my.domain")
 
@@ -44,7 +50,6 @@ class UserIDTestCase(unittest.TestCase):
 
 
 class RoomAliasTestCase(unittest.TestCase):
-
     def test_parse(self):
         room = RoomAlias.from_string("#channel:my.domain")
 
diff --git a/tox.ini b/tox.ini
index a69948484..01b23e6bd 100644
--- a/tox.ini
+++ b/tox.ini
@@ -19,6 +19,7 @@ commands =
     check-manifest
 
 [testenv:pep8]
+skip_install = True
 basepython = python2.7
 deps =
     flake8