diff --git a/src/Factory/ActivityPub/GroupFactory.php b/src/Factory/ActivityPub/GroupFactory.php
index 74aa8159a..464989a08 100644
--- a/src/Factory/ActivityPub/GroupFactory.php
+++ b/src/Factory/ActivityPub/GroupFactory.php
@@ -5,6 +5,8 @@
 namespace App\Factory\ActivityPub;
 
 use App\Entity\Magazine;
+use App\Markdown\MarkdownConverter;
+use App\Markdown\RenderTarget;
 use App\Service\ActivityPub\ContextsProvider;
 use App\Service\ImageManager;
 use Symfony\Component\Routing\Generator\UrlGeneratorInterface;
@@ -13,6 +15,7 @@ class GroupFactory
 {
     public function __construct(
         private readonly UrlGeneratorInterface $urlGenerator,
+        private readonly MarkdownConverter $markdownConverter,
         private readonly ContextsProvider $contextProvider,
         private readonly ImageManager $imageManager
     ) {
@@ -20,6 +23,17 @@ public function __construct(
 
     public function create(Magazine $magazine): array
     {
+        $markdownSummary = $magazine->description;
+
+        if (!empty($magazine->rules)) {
+            $markdownSummary .= "\r\n\r\n### Rules\r\n\r\n".$magazine->rules;
+        }
+
+        $summary = $this->markdownConverter->convertToHtml(
+            $markdownSummary,
+            [MarkdownConverter::RENDER_TARGET => RenderTarget::ActivityPub],
+        );
+
         $group = [
             'type' => 'Group',
             '@context' => $this->contextProvider->referencedContexts(),
@@ -47,7 +61,11 @@ public function create(Magazine $magazine): array
                 'id' => $this->getActivityPubId($magazine).'#main-key',
                 'publicKeyPem' => $magazine->publicKey,
             ],
-            'summary' => $magazine->description,
+            'summary' => $summary,
+            'source' => $markdownSummary ? [
+                'content' => $markdownSummary,
+                'mediaType' => 'text/markdown',
+            ] : null,
             'sensitive' => $magazine->isAdult,
             'attributedTo' => $this->urlGenerator->generate(
                 'ap_magazine_moderators',
diff --git a/src/Service/ActivityPubManager.php b/src/Service/ActivityPubManager.php
index 452c4a41e..91bc49f56 100644
--- a/src/Service/ActivityPubManager.php
+++ b/src/Service/ActivityPubManager.php
@@ -29,6 +29,7 @@
 use App\Repository\MagazineRepository;
 use App\Repository\UserRepository;
 use App\Service\ActivityPub\ApHttpClient;
+use App\Service\ActivityPub\ApObjectExtractor;
 use App\Service\ActivityPub\Webfinger\WebFinger;
 use App\Service\ActivityPub\Webfinger\WebFingerFactory;
 use Doctrine\Common\Collections\Criteria;
@@ -441,8 +442,7 @@ public function updateMagazine(string $actorUrl): ?Magazine
 
         if (isset($actor['endpoints']['sharedInbox']) || isset($actor['inbox'])) {
             if (isset($actor['summary'])) {
-                $converter = new HtmlConverter(['strip_tags' => true]);
-                $magazine->description = stripslashes($converter->convert($actor['summary']));
+                $magazine->description = $this->extractMarkdownSummary($actor);
             }
 
             if (isset($actor['icon'])) {
@@ -789,4 +789,15 @@ public function getEntityObject(string|array $apObject, array $fullPayload, call
 
         return $this->entityManager->getRepository($activity['type'])->find((int) $activity['id']);
     }
+
+    public function extractMarkdownSummary(array $apObject): ?string
+    {
+        if (isset($apObject['source']) && isset($apObject['source']['mediaType']) && isset($apObject['source']['content']) && ApObjectExtractor::MARKDOWN_TYPE === $apObject['source']['mediaType']) {
+            return $apObject['source']['content'];
+        } else {
+            $converter = new HtmlConverter(['strip_tags' => true]);
+
+            return stripslashes($converter->convert($apObject['summary']));
+        }
+    }
 }