diff --git a/src/client_server/room.rs b/src/client_server/room.rs
index 52d25425..a2339639 100644
--- a/src/client_server/room.rs
+++ b/src/client_server/room.rs
@@ -344,10 +344,13 @@ pub async fn create_room_route(
 
     // 6. Events listed in initial_state
     for event in &body.initial_state {
-        let pdu_builder = PduBuilder::from(event.deserialize().map_err(|e| {
+        let mut pdu_builder = event.deserialize_as::<PduBuilder>().map_err(|e| {
             warn!("Invalid initial state event: {:?}", e);
             Error::BadRequest(ErrorKind::InvalidParam, "Invalid initial state event.")
-        })?);
+        })?;
+
+        // Implicit state key defaults to ""
+        pdu_builder.state_key.get_or_insert_with(|| "".to_owned());
 
         // Silently skip encryption events if they are not allowed
         if pdu_builder.event_type == EventType::RoomEncryption && !db.globals.allow_encryption() {
diff --git a/src/pdu.rs b/src/pdu.rs
index db9375e4..fe004609 100644
--- a/src/pdu.rs
+++ b/src/pdu.rs
@@ -1,9 +1,8 @@
 use crate::Error;
 use ruma::{
     events::{
-        room::member::RoomMemberEventContent, AnyEphemeralRoomEvent, AnyInitialStateEvent,
-        AnyRoomEvent, AnyStateEvent, AnyStrippedStateEvent, AnySyncRoomEvent, AnySyncStateEvent,
-        EventType, StateEvent,
+        room::member::RoomMemberEventContent, AnyEphemeralRoomEvent, AnyRoomEvent, AnyStateEvent,
+        AnyStrippedStateEvent, AnySyncRoomEvent, AnySyncStateEvent, EventType, StateEvent,
     },
     serde::{CanonicalJsonObject, CanonicalJsonValue, Raw},
     state_res, EventId, MilliSecondsSinceUnixEpoch, RoomId, RoomVersionId, UInt, UserId,
@@ -361,17 +360,3 @@ pub struct PduBuilder {
     pub state_key: Option<String>,
     pub redacts: Option<Arc<EventId>>,
 }
-
-/// Direct conversion prevents loss of the empty `state_key` that ruma requires.
-impl From<AnyInitialStateEvent> for PduBuilder {
-    fn from(event: AnyInitialStateEvent) -> Self {
-        Self {
-            event_type: EventType::from(event.event_type()),
-            content: to_raw_value(&event.content())
-                .expect("AnyStateEventContent came from JSON and can thus turn back into JSON."),
-            unsigned: None,
-            state_key: Some(event.state_key().to_owned()),
-            redacts: None,
-        }
-    }
-}