diff --git a/src/things/message.ts b/src/things/message.ts
index 1067c1d8..f4cfa82c 100644
--- a/src/things/message.ts
+++ b/src/things/message.ts
@@ -51,6 +51,11 @@ export interface SCMessageWithoutReferences
    */
   messageBody: string;
 
+  /**
+   * An index for applying a custom sorting of multiple messages
+   */
+  sequenceIndex?: number;
+
   /**
    * Translated fields of a message
    */
@@ -119,6 +124,7 @@ export class SCMessageMeta
       audiences: 'Zielgruppen',
       dateCreated: 'Erstellungsdatum',
       messageBody: 'Nachrichteninhalt',
+      sequenceIndex: 'Sequenzindex',
     },
     en: {
       ...SCCreativeWorkMeta.getInstance<SCCreativeWorkMeta>().fieldTranslations
@@ -127,6 +133,7 @@ export class SCMessageMeta
       audiences: 'audiences',
       dateCreated: 'date created',
       messageBody: 'message body',
+      sequenceIndex: 'sequence index',
     },
   };
 
diff --git a/test/resources/Diff.1.json b/test/resources/Diff.1.json
index 283b7c25..4c989323 100644
--- a/test/resources/Diff.1.json
+++ b/test/resources/Diff.1.json
@@ -21,6 +21,7 @@
       "audiences": [
         "students"
       ],
+      "sequenceIndex": 1010,
       "origin": {
         "indexed": "2018-09-11T12:30:00Z",
         "name": "Dummy",
diff --git a/test/resources/Diff.2.json b/test/resources/Diff.2.json
index 6b2611c2..6993b93f 100644
--- a/test/resources/Diff.2.json
+++ b/test/resources/Diff.2.json
@@ -21,6 +21,7 @@
       "audiences": [
         "students"
       ],
+      "sequenceIndex": 1020,
       "origin": {
         "indexed": "2018-09-11T12:30:00Z",
         "name": "Dummy",
diff --git a/test/resources/Message.1.json b/test/resources/Message.1.json
index dad0fe51..a5344e31 100644
--- a/test/resources/Message.1.json
+++ b/test/resources/Message.1.json
@@ -9,6 +9,7 @@
     "audiences": [
       "students"
     ],
+    "sequenceIndex": 1001,
     "origin": {
       "indexed": "2018-09-11T12:30:00Z",
       "name": "Dummy",
diff --git a/test/resources/Message.2.json b/test/resources/Message.2.json
index 238e967b..45df1e6b 100644
--- a/test/resources/Message.2.json
+++ b/test/resources/Message.2.json
@@ -11,6 +11,7 @@
     "audiences": [
       "students"
     ],
+    "sequenceIndex": 1004,
     "origin": {
       "indexed": "2018-09-11T12:30:00Z",
       "name": "foo",
diff --git a/test/resources/Message.3.json b/test/resources/Message.3.json
index ff80f1b4..31921a8e 100644
--- a/test/resources/Message.3.json
+++ b/test/resources/Message.3.json
@@ -17,6 +17,7 @@
       "type": "organization",
       "uid": "4806ef14-b631-5c20-91d1-3c627decca5a"
     }],
+    "sequenceIndex": 1005,
     "origin": {
       "indexed": "2018-09-11T12:30:00Z",
       "name": "Dummy",