diff --git a/crates/ruma-common/src/events/message/content_serde.rs b/crates/ruma-common/src/events/message/content_serde.rs
index a5ee6d44..9a57da59 100644
--- a/crates/ruma-common/src/events/message/content_serde.rs
+++ b/crates/ruma-common/src/events/message/content_serde.rs
@@ -14,6 +14,14 @@ pub(crate) struct MessageContentSerDeHelper {
     #[serde(rename = "org.matrix.msc1767.text")]
     text_unstable: Option<String>,
 
+    /// HTML short form, stable name.
+    #[serde(rename = "m.html")]
+    html_stable: Option<String>,
+
+    /// HTML short form, unstable name.
+    #[serde(rename = "org.matrix.msc1767.html")]
+    html_unstable: Option<String>,
+
     /// Long form, stable name.
     #[serde(rename = "m.message")]
     message_stable: Option<Vec<Text>>,
@@ -30,16 +38,26 @@ impl TryFrom<MessageContentSerDeHelper> for MessageContent {
         let MessageContentSerDeHelper {
             text_stable,
             text_unstable,
+            html_stable,
+            html_unstable,
             message_stable,
             message_unstable,
         } = helper;
 
         if let Some(message) = message_stable.or(message_unstable) {
             Ok(Self(message))
-        } else if let Some(text) = text_stable.or(text_unstable) {
-            Ok(Self::plain(text))
         } else {
-            Err(TryFromExtensibleError::MissingField("m.message or m.text".to_owned()))
+            let message: Vec<_> = html_stable
+                .or(html_unstable)
+                .map(Text::html)
+                .into_iter()
+                .chain(text_stable.or(text_unstable).map(Text::plain))
+                .collect();
+            if !message.is_empty() {
+                Ok(Self(message))
+            } else {
+                Err(TryFromExtensibleError::MissingField("m.message, m.text or m.html".to_owned()))
+            }
         }
     }
 }
@@ -49,13 +67,30 @@ impl Serialize for MessageContent {
     where
         S: serde::Serializer,
     {
-        let mut st = serializer.serialize_struct("MessageContent", 1)?;
-        if self.len() == 1 && self[0].mimetype == "text/plain" {
-            st.serialize_field("org.matrix.msc1767.text", &self[0].body)?;
+        #[cfg(feature = "unstable-msc3554")]
+        let has_shortcut = |message: &Text| {
+            matches!(&*message.mimetype, "text/plain" | "text/html") && message.lang.is_none()
+        };
+
+        #[cfg(not(feature = "unstable-msc3554"))]
+        let has_shortcut =
+            |message: &Text| matches!(&*message.mimetype, "text/plain" | "text/html");
+
+        if self.iter().all(has_shortcut) {
+            let mut st = serializer.serialize_struct("MessageContent", self.len())?;
+            for message in self.iter() {
+                if message.mimetype == "text/plain" {
+                    st.serialize_field("org.matrix.msc1767.text", &message.body)?;
+                } else if message.mimetype == "text/html" {
+                    st.serialize_field("org.matrix.msc1767.html", &message.body)?;
+                }
+            }
+            st.end()
         } else {
+            let mut st = serializer.serialize_struct("MessageContent", 1)?;
             st.serialize_field("org.matrix.msc1767.message", &self.0)?;
+            st.end()
         }
-        st.end()
     }
 }
 
diff --git a/crates/ruma-common/tests/events/audio.rs b/crates/ruma-common/tests/events/audio.rs
index 401d5a65..24b3c035 100644
--- a/crates/ruma-common/tests/events/audio.rs
+++ b/crates/ruma-common/tests/events/audio.rs
@@ -172,10 +172,8 @@ fn event_serialization() {
         to_json_value(&event).unwrap(),
         json!({
             "content": {
-                "org.matrix.msc1767.message": [
-                    { "body": "Upload: <strong>my_mix.mp3</strong>", "mimetype": "text/html"},
-                    { "body": "Upload: my_mix.mp3", "mimetype": "text/plain"},
-                ],
+                "org.matrix.msc1767.html": "Upload: <strong>my_mix.mp3</strong>",
+                "org.matrix.msc1767.text": "Upload: my_mix.mp3",
                 "m.file": {
                     "url": "mxc://notareal.hs/abcdef",
                     "name": "my_mix.mp3",
diff --git a/crates/ruma-common/tests/events/file.rs b/crates/ruma-common/tests/events/file.rs
index 0cdb3477..e55cf818 100644
--- a/crates/ruma-common/tests/events/file.rs
+++ b/crates/ruma-common/tests/events/file.rs
@@ -126,10 +126,8 @@ fn file_event_serialization() {
         to_json_value(&event).unwrap(),
         json!({
             "content": {
-                "org.matrix.msc1767.message": [
-                    { "body": "Upload: <strong>my_file.txt</strong>", "mimetype": "text/html"},
-                    { "body": "Upload: my_file.txt", "mimetype": "text/plain"},
-                ],
+                "org.matrix.msc1767.html": "Upload: <strong>my_file.txt</strong>",
+                "org.matrix.msc1767.text": "Upload: my_file.txt",
                 "m.file": {
                     "url": "mxc://notareal.hs/abcdef",
                     "name": "my_file.txt",
diff --git a/crates/ruma-common/tests/events/image.rs b/crates/ruma-common/tests/events/image.rs
index 1c633b78..b5a5b01f 100644
--- a/crates/ruma-common/tests/events/image.rs
+++ b/crates/ruma-common/tests/events/image.rs
@@ -147,10 +147,8 @@ fn image_event_serialization() {
         to_json_value(&event).unwrap(),
         json!({
             "content": {
-                "org.matrix.msc1767.message": [
-                    { "body": "Upload: <strong>my_house.jpg</strong>", "mimetype": "text/html"},
-                    { "body": "Upload: my_house.jpg", "mimetype": "text/plain"},
-                ],
+                "org.matrix.msc1767.html": "Upload: <strong>my_house.jpg</strong>",
+                "org.matrix.msc1767.text": "Upload: my_house.jpg",
                 "m.file": {
                     "url": "mxc://notareal.hs/abcdef",
                     "name": "my_house.jpg",
diff --git a/crates/ruma-common/tests/events/location.rs b/crates/ruma-common/tests/events/location.rs
index b64cd16c..fd6677a7 100644
--- a/crates/ruma-common/tests/events/location.rs
+++ b/crates/ruma-common/tests/events/location.rs
@@ -70,16 +70,8 @@ fn event_serialization() {
         to_json_value(&event).unwrap(),
         json!({
             "content": {
-                "org.matrix.msc1767.message": [
-                    {
-                        "body": "Alice was at <strong>geo:51.5008,0.1247;u=35</strong> as of <em>Sat Nov 13 18:50:58 2021</em>",
-                        "mimetype": "text/html",
-                    },
-                    {
-                        "body": "Alice was at geo:51.5008,0.1247;u=35 as of Sat Nov 13 18:50:58 2021",
-                        "mimetype": "text/plain",
-                    },
-                ],
+                "org.matrix.msc1767.html": "Alice was at <strong>geo:51.5008,0.1247;u=35</strong> as of <em>Sat Nov 13 18:50:58 2021</em>",
+                "org.matrix.msc1767.text": "Alice was at geo:51.5008,0.1247;u=35 as of Sat Nov 13 18:50:58 2021",
                 "m.location": {
                     "uri": "geo:51.5008,0.1247;u=35",
                     "description": "Alice's whereabouts",
diff --git a/crates/ruma-common/tests/events/message.rs b/crates/ruma-common/tests/events/message.rs
index 16e2429e..c1a76160 100644
--- a/crates/ruma-common/tests/events/message.rs
+++ b/crates/ruma-common/tests/events/message.rs
@@ -37,10 +37,8 @@ fn html_content_serialization() {
     assert_eq!(
         to_json_value(&message_event_content).unwrap(),
         json!({
-            "org.matrix.msc1767.message": [
-                { "body": "Hello, <em>World</em>!", "mimetype": "text/html"},
-                { "body": "Hello, World!", "mimetype": "text/plain"},
-            ]
+            "org.matrix.msc1767.html": "Hello, <em>World</em>!",
+            "org.matrix.msc1767.text": "Hello, World!",
         })
     );
 }
@@ -96,10 +94,8 @@ fn markdown_content_serialization() {
     assert_eq!(
         to_json_value(&formatted_message).unwrap(),
         json!({
-            "org.matrix.msc1767.message": [
-                { "body": "<p>Testing <strong>bold</strong> and <em>italic</em>!</p>\n", "mimetype": "text/html"},
-                { "body": "Testing **bold** and _italic_!", "mimetype": "text/plain"},
-            ]
+            "org.matrix.msc1767.html": "<p>Testing <strong>bold</strong> and <em>italic</em>!</p>\n",
+            "org.matrix.msc1767.text": "Testing **bold** and _italic_!",
         })
     );
 
@@ -118,10 +114,8 @@ fn markdown_content_serialization() {
     assert_eq!(
         to_json_value(&plain_message_paragraphs).unwrap(),
         json!({
-            "org.matrix.msc1767.message": [
-                { "body": "<p>Testing</p>\n<p>Several</p>\n<p>Paragraphs.</p>\n", "mimetype": "text/html"},
-                { "body": "Testing\n\nSeveral\n\nParagraphs.", "mimetype": "text/plain"},
-            ]
+            "org.matrix.msc1767.html": "<p>Testing</p>\n<p>Several</p>\n<p>Paragraphs.</p>\n",
+            "org.matrix.msc1767.text": "Testing\n\nSeveral\n\nParagraphs.",
         })
     );
 }
@@ -198,7 +192,53 @@ fn plain_text_content_stable_deserialization() {
 }
 
 #[test]
-fn html_text_content_unstable_deserialization() {
+fn html_content_unstable_deserialization() {
+    let json_data = json!({
+        "org.matrix.msc1767.html": "Hello, <em>New World</em>!",
+    });
+
+    let content = from_json_value::<MessageEventContent>(json_data).unwrap();
+    assert_eq!(content.message.find_plain(), None);
+    assert_eq!(content.message.find_html(), Some("Hello, <em>New World</em>!"));
+}
+
+#[test]
+fn html_content_stable_deserialization() {
+    let json_data = json!({
+        "m.html": "Hello, <em>New World</em>!",
+    });
+
+    let content = from_json_value::<MessageEventContent>(json_data).unwrap();
+    assert_eq!(content.message.find_plain(), None);
+    assert_eq!(content.message.find_html(), Some("Hello, <em>New World</em>!"));
+}
+
+#[test]
+fn html_and_text_content_unstable_deserialization() {
+    let json_data = json!({
+        "org.matrix.msc1767.html": "Hello, <em>New World</em>!",
+        "org.matrix.msc1767.text": "Hello, New World!",
+    });
+
+    let content = from_json_value::<MessageEventContent>(json_data).unwrap();
+    assert_eq!(content.message.find_plain(), Some("Hello, New World!"));
+    assert_eq!(content.message.find_html(), Some("Hello, <em>New World</em>!"));
+}
+
+#[test]
+fn html_and_text_content_stable_deserialization() {
+    let json_data = json!({
+        "m.html": "Hello, <em>New World</em>!",
+        "m.text": "Hello, New World!",
+    });
+
+    let content = from_json_value::<MessageEventContent>(json_data).unwrap();
+    assert_eq!(content.message.find_plain(), Some("Hello, New World!"));
+    assert_eq!(content.message.find_html(), Some("Hello, <em>New World</em>!"));
+}
+
+#[test]
+fn message_content_unstable_deserialization() {
     let json_data = json!({
         "org.matrix.msc1767.message": [
             { "body": "Hello, <em>New World</em>!", "mimetype": "text/html"},
@@ -212,7 +252,7 @@ fn html_text_content_unstable_deserialization() {
 }
 
 #[test]
-fn html_text_content_stable_deserialization() {
+fn message_content_stable_deserialization() {
     let json_data = json!({
         "m.message": [
             { "body": "Hello, <em>New World</em>!", "mimetype": "text/html"},
@@ -315,7 +355,61 @@ fn room_message_plain_text_unstable_deserialization() {
 }
 
 #[test]
-fn room_message_html_text_stable_deserialization() {
+fn room_message_html_and_text_stable_deserialization() {
+    let json_data = json!({
+        "body": "test",
+        "formatted_body": "<h1>test</h1>",
+        "format": "org.matrix.custom.html",
+        "msgtype": "m.text",
+        "m.html": "<h1>test</h1>",
+        "m.text": "test",
+    });
+
+    let content = assert_matches!(
+        from_json_value::<RoomMessageEventContent>(json_data),
+        Ok(RoomMessageEventContent {
+            msgtype: MessageType::Text(content),
+            ..
+        }) => content
+    );
+    assert_eq!(content.body, "test");
+    let formatted = content.formatted.unwrap();
+    assert_eq!(formatted.body, "<h1>test</h1>");
+    let message = content.message.unwrap();
+    assert_eq!(message.len(), 2);
+    assert_eq!(message[0].body, "<h1>test</h1>");
+    assert_eq!(message[1].body, "test");
+}
+
+#[test]
+fn room_message_html_and_text_unstable_deserialization() {
+    let json_data = json!({
+        "body": "test",
+        "formatted_body": "<h1>test</h1>",
+        "format": "org.matrix.custom.html",
+        "msgtype": "m.text",
+        "org.matrix.msc1767.html": "<h1>test</h1>",
+        "org.matrix.msc1767.text": "test",
+    });
+
+    let content = assert_matches!(
+        from_json_value::<RoomMessageEventContent>(json_data),
+        Ok(RoomMessageEventContent {
+            msgtype: MessageType::Text(content),
+            ..
+        }) => content
+    );
+    assert_eq!(content.body, "test");
+    let formatted = content.formatted.unwrap();
+    assert_eq!(formatted.body, "<h1>test</h1>");
+    let message = content.message.unwrap();
+    assert_eq!(message.len(), 2);
+    assert_eq!(message[0].body, "<h1>test</h1>");
+    assert_eq!(message[1].body, "test");
+}
+
+#[test]
+fn room_message_message_stable_deserialization() {
     let json_data = json!({
         "body": "test",
         "formatted_body": "<h1>test</h1>",
@@ -344,7 +438,7 @@ fn room_message_html_text_stable_deserialization() {
 }
 
 #[test]
-fn room_message_html_text_unstable_deserialization() {
+fn room_message_message_unstable_deserialization() {
     let json_data = json!({
         "body": "test",
         "formatted_body": "<h1>test</h1>",
@@ -537,10 +631,8 @@ fn emote_event_serialization() {
         to_json_value(&event).unwrap(),
         json!({
             "content": {
-                "org.matrix.msc1767.message": [
-                    { "body": "is testing some <code>code</code>…", "mimetype": "text/html" },
-                    { "body": "is testing some code…", "mimetype": "text/plain" },
-                ]
+                "org.matrix.msc1767.html": "is testing some <code>code</code>…",
+                "org.matrix.msc1767.text": "is testing some code…",
             },
             "event_id": "$event:notareal.hs",
             "origin_server_ts": 134_829_848,
diff --git a/crates/ruma-common/tests/events/room_message.rs b/crates/ruma-common/tests/events/room_message.rs
index 9e5f9c6c..c1364cae 100644
--- a/crates/ruma-common/tests/events/room_message.rs
+++ b/crates/ruma-common/tests/events/room_message.rs
@@ -192,10 +192,8 @@ fn formatted_body_serialization() {
             "msgtype": "m.text",
             "format": "org.matrix.custom.html",
             "formatted_body": "Hello, <em>World</em>!",
-            "org.matrix.msc1767.message": [
-                { "body": "Hello, <em>World</em>!", "mimetype": "text/html" },
-                { "body": "Hello, World!", "mimetype": "text/plain" },
-            ],
+            "org.matrix.msc1767.html": "Hello, <em>World</em>!",
+            "org.matrix.msc1767.text": "Hello, World!",
         })
     );
 }
@@ -253,10 +251,8 @@ fn markdown_content_serialization() {
             "formatted_body": "<p>Testing <strong>bold</strong> and <em>italic</em>!</p>\n",
             "format": "org.matrix.custom.html",
             "msgtype": "m.text",
-            "org.matrix.msc1767.message": [
-                { "body": "<p>Testing <strong>bold</strong> and <em>italic</em>!</p>\n", "mimetype": "text/html" },
-                { "body": "Testing **bold** and _italic_!", "mimetype": "text/plain" },
-            ],
+            "org.matrix.msc1767.html": "<p>Testing <strong>bold</strong> and <em>italic</em>!</p>\n",
+            "org.matrix.msc1767.text": "Testing **bold** and _italic_!",
         })
     );
 
@@ -306,10 +302,8 @@ fn markdown_content_serialization() {
             "formatted_body": "<p>Testing</p>\n<p>Several</p>\n<p>Paragraphs.</p>\n",
             "format": "org.matrix.custom.html",
             "msgtype": "m.text",
-            "org.matrix.msc1767.message": [
-                { "body": "<p>Testing</p>\n<p>Several</p>\n<p>Paragraphs.</p>\n", "mimetype": "text/html" },
-                { "body": "Testing\n\nSeveral\n\nParagraphs.", "mimetype": "text/plain" },
-            ],
+            "org.matrix.msc1767.html": "<p>Testing</p>\n<p>Several</p>\n<p>Paragraphs.</p>\n",
+            "org.matrix.msc1767.text": "Testing\n\nSeveral\n\nParagraphs.",
         })
     );
 }
diff --git a/crates/ruma-common/tests/events/video.rs b/crates/ruma-common/tests/events/video.rs
index ce7bca44..b266f9a8 100644
--- a/crates/ruma-common/tests/events/video.rs
+++ b/crates/ruma-common/tests/events/video.rs
@@ -154,10 +154,8 @@ fn event_serialization() {
         to_json_value(&event).unwrap(),
         json!({
             "content": {
-                "org.matrix.msc1767.message": [
-                    { "body": "Upload: <strong>my_lava_lamp.webm</strong>", "mimetype": "text/html"},
-                    { "body": "Upload: my_lava_lamp.webm", "mimetype": "text/plain"},
-                ],
+                "org.matrix.msc1767.html": "Upload: <strong>my_lava_lamp.webm</strong>",
+                "org.matrix.msc1767.text": "Upload: my_lava_lamp.webm",
                 "m.file": {
                     "url": "mxc://notareal.hs/abcdef",
                     "name": "my_lava_lamp.webm",