diff --git a/clientapi/routing/createroom.go b/clientapi/routing/createroom.go
index 220ba6ae8..8c5ee975c 100644
--- a/clientapi/routing/createroom.go
+++ b/clientapi/routing/createroom.go
@@ -15,6 +15,7 @@
 package routing
 
 import (
+	"encoding/json"
 	"fmt"
 	"net/http"
 	"strings"
@@ -97,6 +98,27 @@ func (r createRoomRequest) Validate() *util.JSONResponse {
 		}
 	}
 
+	// Validate creation_content fields defined in the spec by marshalling the
+	// creation_content map into bytes and then unmarshalling the bytes into
+	// common.CreateContent.
+
+	creationContentBytes, err := json.Marshal(r.CreationContent)
+	if err != nil {
+		return &util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON("malformed creation_content"),
+		}
+	}
+
+	var CreationContent common.CreateContent
+	err = json.Unmarshal(creationContentBytes, &CreationContent)
+	if err != nil {
+		return &util.JSONResponse{
+			Code: http.StatusBadRequest,
+			JSON: jsonerror.BadJSON("malformed creation_content"),
+		}
+	}
+
 	return nil
 }
 
@@ -154,7 +176,17 @@ func createRoom(
 			JSON: jsonerror.InvalidArgumentValue(err.Error()),
 		}
 	}
-	// TODO: visibility/presets/raw initial state/creation content
+
+	// Clobber keys: creator, room_version
+
+	if r.CreationContent == nil {
+		r.CreationContent = make(map[string]interface{}, 2)
+	}
+
+	r.CreationContent["creator"] = userID
+	r.CreationContent["room_version"] = "1" // TODO: We set this to 1 before we support Room versioning
+
+	// TODO: visibility/presets/raw initial state
 	// TODO: Create room alias association
 	// Make sure this doesn't fall into an application service's namespace though!
 
@@ -214,7 +246,7 @@ func createRoom(
 	// harder to reason about, hence sticking to a strict static ordering.
 	// TODO: Synapse has txn/token ID on each event. Do we need to do this here?
 	eventsToMake := []fledglingEvent{
-		{"m.room.create", "", common.CreateContent{Creator: userID}},
+		{"m.room.create", "", r.CreationContent},
 		{"m.room.member", userID, membershipContent},
 		{"m.room.power_levels", "", common.InitialPowerLevelsContent(userID)},
 		// TODO: m.room.canonical_alias
diff --git a/common/eventcontent.go b/common/eventcontent.go
index 971c4f0a7..c45724fcd 100644
--- a/common/eventcontent.go
+++ b/common/eventcontent.go
@@ -16,8 +16,16 @@ package common
 
 // CreateContent is the event content for http://matrix.org/docs/spec/client_server/r0.2.0.html#m-room-create
 type CreateContent struct {
-	Creator  string `json:"creator"`
-	Federate *bool  `json:"m.federate,omitempty"`
+	Creator     string       `json:"creator"`
+	Federate    *bool        `json:"m.federate,omitempty"`
+	RoomVersion string       `json:"room_version,omitempty"`
+	Predecessor PreviousRoom `json:"predecessor,omitempty"`
+}
+
+// PreviousRoom is the "Previous Room" structure defined at https://matrix.org/docs/spec/client_server/r0.5.0#m-room-create
+type PreviousRoom struct {
+	RoomID  string `json:"room_id"`
+	EventID string `json:"event_id"`
 }
 
 // MemberContent is the event content for http://matrix.org/docs/spec/client_server/r0.2.0.html#m-room-member
diff --git a/testfile b/testfile
index 1b2ad9e69..4003638f1 100644
--- a/testfile
+++ b/testfile
@@ -151,3 +151,6 @@ Inbound federation of state requires event_id as a mandatory paramater
 Inbound federation of state_ids requires event_id as a mandatory paramater
 POST /register returns the same device_id as that in the request
 POST /login returns the same device_id as that in the request
+POST /createRoom with creation content
+User can create and send/receive messages in a room with version 1
+POST /createRoom ignores attempts to set the room version via creation_content