diff --git a/changelog.d/14070.misc b/changelog.d/14070.misc
new file mode 100644
index 000000000000..6e3d1c5af87d
--- /dev/null
+++ b/changelog.d/14070.misc
@@ -0,0 +1 @@
+Batch up initial power level event when creating rooms.
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index c7d5ef92fc00..bab31e33c5e3 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -15,7 +15,18 @@
 
 import logging
 import typing
-from typing import Any, Collection, Dict, Iterable, List, Optional, Set, Tuple, Union
+from typing import (
+    Any,
+    Collection,
+    Dict,
+    Iterable,
+    List,
+    Mapping,
+    Optional,
+    Set,
+    Tuple,
+    Union,
+)
 
 from canonicaljson import encode_canonical_json
 from signedjson.key import decode_verify_key_bytes
@@ -134,6 +145,7 @@ def validate_event_for_room_version(event: "EventBase") -> None:
 async def check_state_independent_auth_rules(
     store: _EventSourceStore,
     event: "EventBase",
+    batched_auth_events: Optional[Mapping[str, "EventBase"]] = None,
 ) -> None:
     """Check that an event complies with auth rules that are independent of room state
 
@@ -143,6 +155,8 @@ async def check_state_independent_auth_rules(
     Args:
         store: the datastore; used to fetch the auth events for validation
         event: the event being checked.
+        batched_auth_events: if the event being authed is part of a batch, any events
+            from the same batch that may be necessary to auth the current event
 
     Raises:
         AuthError if the checks fail
@@ -162,6 +176,9 @@ async def check_state_independent_auth_rules(
         redact_behaviour=EventRedactBehaviour.as_is,
         allow_rejected=True,
     )
+    if batched_auth_events:
+        auth_events.update(batched_auth_events)
+
     room_id = event.room_id
     auth_dict: MutableStateMap[str] = {}
     expected_auth_types = auth_types_for_event(event.room_version, event)
diff --git a/synapse/handlers/event_auth.py b/synapse/handlers/event_auth.py
index 8249ca1ed26c..3bbad0271bcc 100644
--- a/synapse/handlers/event_auth.py
+++ b/synapse/handlers/event_auth.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import logging
-from typing import TYPE_CHECKING, Collection, List, Optional, Union
+from typing import TYPE_CHECKING, Collection, List, Mapping, Optional, Union
 
 from synapse import event_auth
 from synapse.api.constants import (
@@ -29,7 +29,6 @@
 )
 from synapse.events import EventBase
 from synapse.events.builder import EventBuilder
-from synapse.events.snapshot import EventContext
 from synapse.types import StateMap, get_domain_from_id
 
 if TYPE_CHECKING:
@@ -51,12 +50,21 @@ def __init__(self, hs: "HomeServer"):
     async def check_auth_rules_from_context(
         self,
         event: EventBase,
-        context: EventContext,
+        batched_auth_events: Optional[Mapping[str, EventBase]] = None,
     ) -> None:
-        """Check an event passes the auth rules at its own auth events"""
-        await check_state_independent_auth_rules(self._store, event)
+        """Check an event passes the auth rules at its own auth events
+        Args:
+            event: event to be authed
+            batched_auth_events: if the event being authed is part of a batch, any events
+            from the same batch that may be necessary to auth the current event
+        """
+        await check_state_independent_auth_rules(
+            self._store, event, batched_auth_events
+        )
         auth_event_ids = event.auth_event_ids()
         auth_events_by_id = await self._store.get_events(auth_event_ids)
+        if batched_auth_events:
+            auth_events_by_id.update(batched_auth_events)
         check_state_dependent_auth_rules(event, auth_events_by_id.values())
 
     def compute_auth_events(
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 986ffed3d592..3f2eed07536c 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -928,7 +928,7 @@ async def on_make_join_request(
 
         # The remote hasn't signed it yet, obviously. We'll do the full checks
         # when we get the event back in `on_send_join_request`
-        await self._event_auth_handler.check_auth_rules_from_context(event, context)
+        await self._event_auth_handler.check_auth_rules_from_context(event)
         return event
 
     async def on_invite_request(
@@ -1003,7 +1003,9 @@ async def on_invite_request(
 
         context = EventContext.for_outlier(self._storage_controllers)
 
-        await self._bulk_push_rule_evaluator.action_for_event_by_user(event, context)
+        await self._bulk_push_rule_evaluator.action_for_event_by_user(
+            [(event, context)]
+        )
         try:
             await self._federation_event_handler.persist_events_and_notify(
                 event.room_id, [(event, context)]
@@ -1109,7 +1111,7 @@ async def on_make_leave_request(
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_leave_request`
-            await self._event_auth_handler.check_auth_rules_from_context(event, context)
+            await self._event_auth_handler.check_auth_rules_from_context(event)
         except AuthError as e:
             logger.warning("Failed to create new leave %r because %s", event, e)
             raise e
@@ -1168,7 +1170,7 @@ async def on_make_knock_request(
         try:
             # The remote hasn't signed it yet, obviously. We'll do the full checks
             # when we get the event back in `on_send_knock_request`
-            await self._event_auth_handler.check_auth_rules_from_context(event, context)
+            await self._event_auth_handler.check_auth_rules_from_context(event)
         except AuthError as e:
             logger.warning("Failed to create new knock %r because %s", event, e)
             raise e
@@ -1334,9 +1336,7 @@ async def exchange_third_party_invite(
 
             try:
                 validate_event_for_room_version(event)
-                await self._event_auth_handler.check_auth_rules_from_context(
-                    event, context
-                )
+                await self._event_auth_handler.check_auth_rules_from_context(event)
             except AuthError as e:
                 logger.warning("Denying new third party invite %r because %s", event, e)
                 raise e
@@ -1386,7 +1386,7 @@ async def on_exchange_third_party_invite_request(
 
         try:
             validate_event_for_room_version(event)
-            await self._event_auth_handler.check_auth_rules_from_context(event, context)
+            await self._event_auth_handler.check_auth_rules_from_context(event)
         except AuthError as e:
             logger.warning("Denying third party invite %r because %s", event, e)
             raise e
diff --git a/synapse/handlers/federation_event.py b/synapse/handlers/federation_event.py
index da319943cc19..9be7c094c4bf 100644
--- a/synapse/handlers/federation_event.py
+++ b/synapse/handlers/federation_event.py
@@ -2118,7 +2118,7 @@ async def _run_push_actions_and_persist_event(
                 )
             else:
                 await self._bulk_push_rule_evaluator.action_for_event_by_user(
-                    event, context
+                    [(event, context)]
                 )
 
         try:
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index da1acea2755b..05bbbb331a9f 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -1360,8 +1360,16 @@ async def handle_new_client_event(
             else:
                 try:
                     validate_event_for_room_version(event)
+                    # If we are persisting a batch of events the event(s) needed to auth the
+                    # current event may be part of the batch and will not be in the DB yet
+                    event_id_to_event = {e.event_id: e for e, _ in events_and_context}
+                    batched_auth_events = {}
+                    for event_id in event.auth_event_ids():
+                        auth_event = event_id_to_event.get(event_id)
+                        if auth_event:
+                            batched_auth_events[event_id] = auth_event
                     await self._event_auth_handler.check_auth_rules_from_context(
-                        event, context
+                        event, batched_auth_events
                     )
                 except AuthError as err:
                     logger.warning("Denying new event %r because %s", event, err)
@@ -1424,18 +1432,10 @@ async def _persist_events(
         PartialStateConflictError: if attempting to persist a partial state event in
             a room that has been un-partial stated.
         """
-
-        for event, context in events_and_context:
-            # Skip push notification actions for historical messages
-            # because we don't want to notify people about old history back in time.
-            # The historical messages also do not have the proper `context.current_state_ids`
-            # and `state_groups` because they have `prev_events` that aren't persisted yet
-            # (historical messages persisted in reverse-chronological order).
-            if not event.internal_metadata.is_historical():
-                with opentracing.start_active_span("calculate_push_actions"):
-                    await self._bulk_push_rule_evaluator.action_for_event_by_user(
-                        event, context
-                    )
+        with opentracing.start_active_span("calculate_push_actions"):
+            await self._bulk_push_rule_evaluator.action_for_event_by_user(
+                events_and_context
+            )
 
         try:
             # If we're a worker we need to hit out to the master.
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 57ab05ad25d9..f6030a7ad50c 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -229,9 +229,7 @@ async def upgrade_room(
             },
         )
         validate_event_for_room_version(tombstone_event)
-        await self._event_auth_handler.check_auth_rules_from_context(
-            tombstone_event, tombstone_context
-        )
+        await self._event_auth_handler.check_auth_rules_from_context(tombstone_event)
 
         # Upgrade the room
         #
@@ -1159,6 +1157,7 @@ async def send(
         depth += 1
         state_map[(EventTypes.Member, creator.user.to_string())] = member_event_id
 
+        events_to_send = []
         # We treat the power levels override specially as this needs to be one
         # of the first events that get sent into a room.
         pl_content = initial_state.pop((EventTypes.PowerLevels, ""), None)
@@ -1167,7 +1166,7 @@ async def send(
                 EventTypes.PowerLevels, pl_content, False
             )
             current_state_group = power_context._state_group
-            await send(power_event, power_context, creator)
+            events_to_send.append((power_event, power_context))
         else:
             power_level_content: JsonDict = {
                 "users": {creator_id: 100},
@@ -1216,9 +1215,8 @@ async def send(
                 False,
             )
             current_state_group = pl_context._state_group
-            await send(pl_event, pl_context, creator)
+            events_to_send.append((pl_event, pl_context))
 
-        events_to_send = []
         if room_alias and (EventTypes.CanonicalAlias, "") not in initial_state:
             room_alias_event, room_alias_context = await create_event(
                 EventTypes.CanonicalAlias, {"alias": room_alias.to_string()}, True
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index eced182fd571..2ecfdf2951e6 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -171,7 +171,10 @@ async def _get_rules_for_event(
         return rules_by_user
 
     async def _get_power_levels_and_sender_level(
-        self, event: EventBase, context: EventContext
+        self,
+        event: EventBase,
+        context: EventContext,
+        event_id_to_event: Mapping[str, EventBase],
     ) -> Tuple[dict, Optional[int]]:
         # There are no power levels and sender levels possible to get from outlier
         if event.internal_metadata.is_outlier():
@@ -183,15 +186,26 @@ async def _get_power_levels_and_sender_level(
         )
         pl_event_id = prev_state_ids.get(POWER_KEY)
 
+        # fastpath: if there's a power level event, that's all we need, and
+        # not having a power level event is an extreme edge case
         if pl_event_id:
-            # fastpath: if there's a power level event, that's all we need, and
-            # not having a power level event is an extreme edge case
-            auth_events = {POWER_KEY: await self.store.get_event(pl_event_id)}
+            # check that the power level event is not in the batch before checking the DB
+            pl_event = event_id_to_event.get(pl_event_id)
+            if pl_event:
+                auth_events = {POWER_KEY: pl_event}
+            else:
+                auth_events = {POWER_KEY: await self.store.get_event(pl_event_id)}
         else:
             auth_events_ids = self._event_auth_handler.compute_auth_events(
                 event, prev_state_ids, for_verification=False
             )
             auth_events_dict = await self.store.get_events(auth_events_ids)
+            # check to see that there aren't any needed auth events in the batch as it
+            # hasn't been persisted yet
+            for auth_event_id in auth_events_ids:
+                auth_event = event_id_to_event.get(auth_event_id)
+                if auth_event:
+                    auth_events_dict[auth_event_id] = auth_event
             auth_events = {(e.type, e.state_key): e for e in auth_events_dict.values()}
 
         sender_level = get_user_power_level(event.sender, auth_events)
@@ -247,132 +261,148 @@ async def _get_mutual_relations(
 
     @measure_func("action_for_event_by_user")
     async def action_for_event_by_user(
-        self, event: EventBase, context: EventContext
+        self, events_and_context: List[Tuple[EventBase, EventContext]]
     ) -> None:
-        """Given an event and context, evaluate the push rules, check if the message
-        should increment the unread count, and insert the results into the
-        event_push_actions_staging table.
+        """Given a list of events and their associated contexts, evaluate the push rules
+        for each event, check if the message should increment the unread count, and
+        insert the results into the event_push_actions_staging table.
         """
-        if not event.internal_metadata.is_notifiable():
-            # Push rules for events that aren't notifiable can't be processed by this
-            return
-
-        # Disable counting as unread unless the experimental configuration is
-        # enabled, as it can cause additional (unwanted) rows to be added to the
-        # event_push_actions table.
-        count_as_unread = False
-        if self.hs.config.experimental.msc2654_enabled:
-            count_as_unread = _should_count_as_unread(event, context)
-
-        rules_by_user = await self._get_rules_for_event(event)
-        actions_by_user: Dict[str, Collection[Union[Mapping, str]]] = {}
-
-        room_member_count = await self.store.get_number_joined_users_in_room(
-            event.room_id
-        )
+        for event, context in events_and_context:
+            if not event.internal_metadata.is_notifiable():
+                # Push rules for events that aren't notifiable can't be processed by this
+                return
+            # Skip push notification actions for historical messages
+            # because we don't want to notify people about old history back in time.
+            # The historical messages also do not have the proper `context.current_state_ids`
+            # and `state_groups` because they have `prev_events` that aren't persisted yet
+            # (historical messages persisted in reverse-chronological order).
+            if event.internal_metadata.is_historical():
+                return
+
+            # Disable counting as unread unless the experimental configuration is
+            # enabled, as it can cause additional (unwanted) rows to be added to the
+            # event_push_actions table.
+            count_as_unread = False
+            if self.hs.config.experimental.msc2654_enabled:
+                count_as_unread = _should_count_as_unread(event, context)
+
+            rules_by_user = await self._get_rules_for_event(event)
+            actions_by_user: Dict[str, Collection[Union[Mapping, str]]] = {}
+
+            room_member_count = await self.store.get_number_joined_users_in_room(
+                event.room_id
+            )
 
-        (
-            power_levels,
-            sender_power_level,
-        ) = await self._get_power_levels_and_sender_level(event, context)
-
-        relation = relation_from_event(event)
-        # If the event does not have a relation, then cannot have any mutual
-        # relations or thread ID.
-        relations = {}
-        thread_id = MAIN_TIMELINE
-        if relation:
-            relations = await self._get_mutual_relations(
-                relation.parent_id,
-                itertools.chain(*(r.rules() for r in rules_by_user.values())),
+            # For batched events the power level events may not have been persisted yet,
+            # so we pass in the batched events. Thus if the event cannot be found in the
+            # database we can check in the batch.
+            event_id_to_event = {e.event_id: e for e, _ in events_and_context}
+            (
+                power_levels,
+                sender_power_level,
+            ) = await self._get_power_levels_and_sender_level(
+                event, context, event_id_to_event
             )
-            # Recursively attempt to find the thread this event relates to.
-            if relation.rel_type == RelationTypes.THREAD:
-                thread_id = relation.parent_id
-            else:
-                # Since the event has not yet been persisted we check whether
-                # the parent is part of a thread.
-                thread_id = await self.store.get_thread_id(relation.parent_id) or "main"
-
-        # It's possible that old room versions have non-integer power levels (floats or
-        # strings). Workaround this by explicitly converting to int.
-        notification_levels = power_levels.get("notifications", {})
-        if not event.room_version.msc3667_int_only_power_levels:
-            for user_id, level in notification_levels.items():
-                notification_levels[user_id] = int(level)
-
-        evaluator = PushRuleEvaluator(
-            _flatten_dict(event),
-            room_member_count,
-            sender_power_level,
-            notification_levels,
-            relations,
-            self._relations_match_enabled,
-        )
 
-        users = rules_by_user.keys()
-        profiles = await self.store.get_subset_users_in_room_with_profiles(
-            event.room_id, users
-        )
+            relation = relation_from_event(event)
+            # If the event does not have a relation, then cannot have any mutual
+            # relations or thread ID.
+            relations = {}
+            thread_id = MAIN_TIMELINE
+            if relation:
+                relations = await self._get_mutual_relations(
+                    relation.parent_id,
+                    itertools.chain(*(r.rules() for r in rules_by_user.values())),
+                )
+                # Recursively attempt to find the thread this event relates to.
+                if relation.rel_type == RelationTypes.THREAD:
+                    thread_id = relation.parent_id
+                else:
+                    # Since the event has not yet been persisted we check whether
+                    # the parent is part of a thread.
+                    thread_id = (
+                        await self.store.get_thread_id(relation.parent_id) or "main"
+                    )
+
+            # It's possible that old room versions have non-integer power levels (floats or
+            # strings). Workaround this by explicitly converting to int.
+            notification_levels = power_levels.get("notifications", {})
+            if not event.room_version.msc3667_int_only_power_levels:
+                for user_id, level in notification_levels.items():
+                    notification_levels[user_id] = int(level)
+
+            evaluator = PushRuleEvaluator(
+                _flatten_dict(event),
+                room_member_count,
+                sender_power_level,
+                notification_levels,
+                relations,
+                self._relations_match_enabled,
+            )
 
-        for uid, rules in rules_by_user.items():
-            if event.sender == uid:
-                continue
+            users = rules_by_user.keys()
+            profiles = await self.store.get_subset_users_in_room_with_profiles(
+                event.room_id, users
+            )
 
-            display_name = None
-            profile = profiles.get(uid)
-            if profile:
-                display_name = profile.display_name
-
-            if not display_name:
-                # Handle the case where we are pushing a membership event to
-                # that user, as they might not be already joined.
-                if event.type == EventTypes.Member and event.state_key == uid:
-                    display_name = event.content.get("displayname", None)
-                    if not isinstance(display_name, str):
-                        display_name = None
-
-            if count_as_unread:
-                # Add an element for the current user if the event needs to be marked as
-                # unread, so that add_push_actions_to_staging iterates over it.
-                # If the event shouldn't be marked as unread but should notify the
-                # current user, it'll be added to the dict later.
-                actions_by_user[uid] = []
-
-            actions = evaluator.run(rules, uid, display_name)
-            if "notify" in actions:
-                # Push rules say we should notify the user of this event
-                actions_by_user[uid] = actions
-
-        # If there aren't any actions then we can skip the rest of the
-        # processing.
-        if not actions_by_user:
-            return
-
-        # This is a check for the case where user joins a room without being
-        # allowed to see history, and then the server receives a delayed event
-        # from before the user joined, which they should not be pushed for
-        #
-        # We do this *after* calculating the push actions as a) its unlikely
-        # that we'll filter anyone out and b) for large rooms its likely that
-        # most users will have push disabled and so the set of users to check is
-        # much smaller.
-        uids_with_visibility = await filter_event_for_clients_with_state(
-            self.store, actions_by_user.keys(), event, context
-        )
+            for uid, rules in rules_by_user.items():
+                if event.sender == uid:
+                    continue
 
-        for user_id in set(actions_by_user).difference(uids_with_visibility):
-            actions_by_user.pop(user_id, None)
-
-        # Mark in the DB staging area the push actions for users who should be
-        # notified for this event. (This will then get handled when we persist
-        # the event)
-        await self.store.add_push_actions_to_staging(
-            event.event_id,
-            actions_by_user,
-            count_as_unread,
-            thread_id,
-        )
+                display_name = None
+                profile = profiles.get(uid)
+                if profile:
+                    display_name = profile.display_name
+
+                if not display_name:
+                    # Handle the case where we are pushing a membership event to
+                    # that user, as they might not be already joined.
+                    if event.type == EventTypes.Member and event.state_key == uid:
+                        display_name = event.content.get("displayname", None)
+                        if not isinstance(display_name, str):
+                            display_name = None
+
+                if count_as_unread:
+                    # Add an element for the current user if the event needs to be marked as
+                    # unread, so that add_push_actions_to_staging iterates over it.
+                    # If the event shouldn't be marked as unread but should notify the
+                    # current user, it'll be added to the dict later.
+                    actions_by_user[uid] = []
+
+                actions = evaluator.run(rules, uid, display_name)
+                if "notify" in actions:
+                    # Push rules say we should notify the user of this event
+                    actions_by_user[uid] = actions
+
+            # If there aren't any actions then we can skip the rest of the
+            # processing.
+            if not actions_by_user:
+                return
+
+            # This is a check for the case where user joins a room without being
+            # allowed to see history, and then the server receives a delayed event
+            # from before the user joined, which they should not be pushed for
+            #
+            # We do this *after* calculating the push actions as a) its unlikely
+            # that we'll filter anyone out and b) for large rooms its likely that
+            # most users will have push disabled and so the set of users to check is
+            # much smaller.
+            uids_with_visibility = await filter_event_for_clients_with_state(
+                self.store, actions_by_user.keys(), event, context
+            )
+
+            for user_id in set(actions_by_user).difference(uids_with_visibility):
+                actions_by_user.pop(user_id, None)
+
+            # Mark in the DB staging area the push actions for users who should be
+            # notified for this event. (This will then get handled when we persist
+            # the event)
+            await self.store.add_push_actions_to_staging(
+                event.event_id,
+                actions_by_user,
+                count_as_unread,
+                thread_id,
+            )
 
 
 MemberMap = Dict[str, Optional[EventIdMembership]]
diff --git a/tests/push/test_bulk_push_rule_evaluator.py b/tests/push/test_bulk_push_rule_evaluator.py
index 675d7df2ac45..4d8bee3fda8e 100644
--- a/tests/push/test_bulk_push_rule_evaluator.py
+++ b/tests/push/test_bulk_push_rule_evaluator.py
@@ -71,4 +71,4 @@ def test_action_for_event_by_user_handles_noninteger_power_levels(self) -> None:
 
         bulk_evaluator = BulkPushRuleEvaluator(self.hs)
         # should not raise
-        self.get_success(bulk_evaluator.action_for_event_by_user(event, context))
+        self.get_success(bulk_evaluator.action_for_event_by_user([(event, context)]))
diff --git a/tests/replication/_base.py b/tests/replication/_base.py
index ce53f808db9a..121f3d8d6517 100644
--- a/tests/replication/_base.py
+++ b/tests/replication/_base.py
@@ -371,7 +371,7 @@ def make_worker_hs(
             config=worker_hs.config.server.listeners[0],
             resource=resource,
             server_version_string="1",
-            max_request_body_size=4096,
+            max_request_body_size=8192,
             reactor=self.reactor,
         )
 
diff --git a/tests/rest/client/test_rooms.py b/tests/rest/client/test_rooms.py
index 3612ebe7b961..8e67c207e7e0 100644
--- a/tests/rest/client/test_rooms.py
+++ b/tests/rest/client/test_rooms.py
@@ -711,7 +711,7 @@ def test_post_room_no_keys(self) -> None:
         self.assertEqual(HTTPStatus.OK, channel.code, channel.result)
         self.assertTrue("room_id" in channel.json_body)
         assert channel.resource_usage is not None
-        self.assertEqual(34, channel.resource_usage.db_txn_count)
+        self.assertEqual(31, channel.resource_usage.db_txn_count)
 
     def test_post_room_initial_state(self) -> None:
         # POST with initial_state config key, expect new room id
@@ -724,7 +724,7 @@ def test_post_room_initial_state(self) -> None:
         self.assertEqual(HTTPStatus.OK, channel.code, channel.result)
         self.assertTrue("room_id" in channel.json_body)
         assert channel.resource_usage is not None
-        self.assertEqual(37, channel.resource_usage.db_txn_count)
+        self.assertEqual(33, channel.resource_usage.db_txn_count)
 
     def test_post_room_visibility_key(self) -> None:
         # POST with visibility config key, expect new room id