diff --git a/lib/SimpleSAML/XML/SAML20/AuthnResponse.php b/lib/SimpleSAML/XML/SAML20/AuthnResponse.php
index 986fbc5a1552d79ff7b9ed0952c551dbbbaf9eb6..e8f890e859c8c11227044edd76b8fb15de5f798c 100644
--- a/lib/SimpleSAML/XML/SAML20/AuthnResponse.php
+++ b/lib/SimpleSAML/XML/SAML20/AuthnResponse.php
@@ -37,6 +37,13 @@ class SimpleSAML_XML_SAML20_AuthnResponse extends SimpleSAML_XML_AuthnResponse {
 	
 	const TRANSIENT 	= 'urn:oasis:names:tc:SAML:2.0:nameid-format:transient';
 	const EMAIL 		= 'urn:oasis:names:tc:SAML:2.0:nameid-format:email';
+
+	/* Namespaces used in the XML representation of this object.
+	 * TODO: Move these constants into a generic SAML2-class?
+	 */
+	const SAML2_ASSERT_NS = 'urn:oasis:names:tc:SAML:2.0:assertion';
+	const SAML2_PROTOCOL_NS = 'urn:oasis:names:tc:SAML:2.0:protocol';
+	
 	
 
 	function __construct(SimpleSAML_Configuration $configuration, SimpleSAML_XML_MetaDataStore $metadatastore) {
@@ -196,9 +203,6 @@ class SimpleSAML_XML_SAML20_AuthnResponse extends SimpleSAML_XML_AuthnResponse {
 		
 		$base64 = isset($md['base64attributes']) ? $md['base64attributes'] : false;
 		
-		define('SAML2_ASSERT_NS', 'urn:oasis:names:tc:SAML:2.0:assertion');
-		define('SAML2_PROTOCOL_NS', 'urn:oasis:names:tc:SAML:2.0:protocol');
-		
 		define('SAML2_BINDINGS_POST', 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-POST');
 		
 		define('SAML2_STATUS_SUCCESS', 'urn:oasis:names:tc:SAML:2.0:status:Success');