diff --git a/src/ORM/Hierarchy/MarkedSet.php b/src/ORM/Hierarchy/MarkedSet.php
index c82a22aac4f..c4cd52daace 100644
--- a/src/ORM/Hierarchy/MarkedSet.php
+++ b/src/ORM/Hierarchy/MarkedSet.php
@@ -420,9 +420,15 @@ protected function getSubtree($node, $depth = 0)
             'expanded' => $expanded,
             'opened' => $opened,
             'depth' => $depth,
-            'count' => $count, // Count of DB children
-            'limited' => $limited, // Flag whether 'items' has been limited
-            'children' => [], // Children to return in this request
+            // Used for aria-level, the root level "Your site name" is aria-level 1
+            // A default page like "Home" or "About us" is aria-level 2
+            'level' => $depth + 1,
+            // Count of DB children
+            'count' => $count,
+            // Flag whether 'items' has been limited
+            'limited' => $limited,
+            // Children to return in this request
+            'children' => [],
         ];
 
         // Don't iterate children if past limit