diff --git a/KorAP_schemas/span.rng b/KorAP_schemas/span.rng
index feb2835..5314cf7 100644
--- a/KorAP_schemas/span.rng
+++ b/KorAP_schemas/span.rng
@@ -77,9 +77,11 @@
           <data type="NCName"/>
         </attribute>
       </optional>-->
-      <attribute name="l">
-        <data type="integer"/>
-      </attribute>
+      <optional>
+        <attribute name="l">
+          <data type="integer"/>
+        </attribute>
+      </optional>
       <attribute name="from">
         <choice>
           <data type="integer"/>