diff --git a/lib/SimpleSAML/XML/Shib13/AuthnResponse.php b/lib/SimpleSAML/XML/Shib13/AuthnResponse.php
index 507f6b0ca5c8d07a7f0f23fcf6fb239838215d9c..1f5bef1ea4a9e5acef8ef5ffd9e8f26915321e91 100644
--- a/lib/SimpleSAML/XML/Shib13/AuthnResponse.php
+++ b/lib/SimpleSAML/XML/Shib13/AuthnResponse.php
@@ -210,7 +210,7 @@ class SimpleSAML_XML_Shib13_AuthnResponse extends SimpleSAML_XML_AuthnResponse {
 		if ($attr = $nodelist->item(0)) {
 			return $attr->value;
 		} else {
-			throw Exception('Could not find Issuer field in Authentication response');
+			throw new Exception('Could not find Issuer field in Authentication response');
 		}
 
 	}