diff --git a/src/XML/fed/SecurityTokenServiceType.php b/src/XML/fed/SecurityTokenServiceType.php
index 0841fc1b..998d34bc 100644
--- a/src/XML/fed/SecurityTokenServiceType.php
+++ b/src/XML/fed/SecurityTokenServiceType.php
@@ -22,6 +22,10 @@
  */
 final class SecurityTokenServiceType extends AbstractSecurityTokenServiceType
 {
+    /** @var string */
+    public const LOCALNAME = 'RoleDescriptor';
+
+
     /**
      * Convert XML into a SecurityTokenServiceType RoleDescriptor
      *