diff --git a/lib/SimpleSAML/Metadata/SAMLBuilder.php b/lib/SimpleSAML/Metadata/SAMLBuilder.php
index a3d090e2c375d7d59c11052e69e9eb2fbde3720f..bc06cd5283da667cc61ff6eb006bdb13fa9ebb29 100644
--- a/lib/SimpleSAML/Metadata/SAMLBuilder.php
+++ b/lib/SimpleSAML/Metadata/SAMLBuilder.php
@@ -464,7 +464,7 @@ class SimpleSAML_Metadata_SAMLBuilder {
 
 		$metadata = SimpleSAML_Configuration::loadFromArray($metadata, $metadata['entityid']);
 
-		$e = new SAMl2_AttributeAuthorityDescriptor();
+		$e = new SAML2_XML_md_AttributeAuthorityDescriptor();
 		$e->protocolSupportEnumeration = $metadata->getArray('protocols', array());
 
 		$this->addExtensions($metadata, $e);