diff --git a/src/matrix/room/sending/PendingEvent.js b/src/matrix/room/sending/PendingEvent.js
index 7738847f..731707e5 100644
--- a/src/matrix/room/sending/PendingEvent.js
+++ b/src/matrix/room/sending/PendingEvent.js
@@ -16,7 +16,7 @@ limitations under the License.
 import {createEnum} from "../../../utils/enum.js";
 import {AbortError} from "../../../utils/error.js";
 import {REDACTION_TYPE} from "../common.js";
-import {getRelationFromContent} from "../timeline/relations.js";
+import {getRelationFromContent, getRelationTarget, setRelationTarget} from "../timeline/relations.js";
 
 export const SendStatus = createEnum(
     "Waiting",
@@ -54,7 +54,7 @@ export class PendingEvent {
         const relation = getRelationFromContent(this.content);
         if (relation) {
             // may be null when target is not sent yet, is intended
-            return relation.event_id;
+            return getRelationTarget(relation);
         } else {
             return this._data.relatedEventId;
         }
@@ -63,7 +63,7 @@ export class PendingEvent {
     setRelatedEventId(eventId) {
         const relation = getRelationFromContent(this.content);
         if (relation) {
-            relation.event_id = eventId;
+            setRelationTarget(relation, eventId);
         } else {
             this._data.relatedEventId = eventId;
         }
diff --git a/src/matrix/room/sending/SendQueue.js b/src/matrix/room/sending/SendQueue.js
index d6b16ac1..dd562610 100644
--- a/src/matrix/room/sending/SendQueue.js
+++ b/src/matrix/room/sending/SendQueue.js
@@ -19,7 +19,7 @@ import {ConnectionError} from "../../error.js";
 import {PendingEvent, SendStatus} from "./PendingEvent.js";
 import {makeTxnId, isTxnId} from "../../common.js";
 import {REDACTION_TYPE} from "../common.js";
-import {getRelationFromContent, REACTION_TYPE, ANNOTATION_RELATION_TYPE} from "../timeline/relations.js";
+import {getRelationFromContent, getRelationTarget, setRelationTarget, REACTION_TYPE, ANNOTATION_RELATION_TYPE} from "../timeline/relations.js";
 
 export class SendQueue {
     constructor({roomId, storage, hsApi, pendingEvents}) {
@@ -206,11 +206,13 @@ export class SendQueue {
         const relation = getRelationFromContent(content);
         let relatedTxnId = null;
         if (relation) {
-            if (isTxnId(relation.event_id)) {
-                relatedTxnId = relation.event_id;
-                relation.event_id = null;
+            const relationTarget = getRelationTarget(relation);
+            if (isTxnId(relationTarget)) {
+                relatedTxnId = relationTarget;
+                setRelationTarget(relation, null);
             }
             if (relation.rel_type === ANNOTATION_RELATION_TYPE) {
+                // Here we know the shape of the relation, and can use event_id safely
                 const isAlreadyAnnotating = this._pendingEvents.array.some(pe => {
                     const r = getRelationFromContent(pe.content);
                     return pe.eventType === eventType && r && r.key === relation.key &&
diff --git a/src/matrix/room/timeline/persistence/RelationWriter.js b/src/matrix/room/timeline/persistence/RelationWriter.js
index b56988be..4944cc64 100644
--- a/src/matrix/room/timeline/persistence/RelationWriter.js
+++ b/src/matrix/room/timeline/persistence/RelationWriter.js
@@ -30,7 +30,8 @@ export class RelationWriter {
         const {relatedEventId} = sourceEntry;
         if (relatedEventId) {
             const relation = getRelation(sourceEntry.event);
-            if (relation) {
+            if (relation && relation.rel_type) {
+                // we don't consider replies (which aren't relations in the MSC2674 sense)
                 txn.timelineRelations.add(this._roomId, relation.event_id, relation.rel_type, sourceEntry.id);
             }
             const target = await txn.timelineEvents.getByEventId(this._roomId, relatedEventId);
@@ -120,7 +121,7 @@ export class RelationWriter {
         log.set("id", redactedEvent.event_id);
 
         const relation = getRelation(redactedEvent);
-        if (relation) {
+        if (relation && relation.rel_type) {
             txn.timelineRelations.remove(this._roomId, relation.event_id, relation.rel_type, redactedEvent.event_id);
         }
         // check if we're the target of a relation and remove all relations then as well
diff --git a/src/matrix/room/timeline/relations.js b/src/matrix/room/timeline/relations.js
index 5bf0f490..4009d8c4 100644
--- a/src/matrix/room/timeline/relations.js
+++ b/src/matrix/room/timeline/relations.js
@@ -29,13 +29,25 @@ export function createAnnotation(targetId, key) {
     };
 }
 
+export function getRelationTarget(relation) {
+    return relation.event_id || relation["m.in_reply_to"]?.event_id
+}
+
+export function setRelationTarget(relation, target) {
+    if (relation.event_id !== undefined) {
+        relation.event_id = target;
+    } else if (relation["m.in_reply_to"]) {
+        relation["m.in_reply_to"].event_id = target;
+    }
+}
+
 export function getRelatedEventId(event) {
 	if (event.type === REDACTION_TYPE) {
         return event.redacts;
     } else {
         const relation = getRelation(event);
         if (relation) {
-            return relation.event_id;
+            return getRelationTarget(relation);
         }
     }
     return null;