diff --git a/modules/saml/www/sp/saml2-acs.php b/modules/saml/www/sp/saml2-acs.php
index 194e00954d51fbd7d02ec8530c3ed54a0797705a..2e6b45371354793c7d915c125726c651152ed6d7 100644
--- a/modules/saml/www/sp/saml2-acs.php
+++ b/modules/saml/www/sp/saml2-acs.php
@@ -231,6 +231,8 @@ $state['LogoutState'] = $logoutState;
 $state['saml:AuthenticatingAuthority'] = $authenticatingAuthority;
 $state['saml:AuthenticatingAuthority'][] = $idp;
 $state['PersistentAuthData'][] = 'saml:AuthenticatingAuthority';
+$state['saml:AuthnInstant'] = $assertion->getAuthnInstant();
+$state['PersistentAuthData'][] = 'saml:AuthnInstant';
 $state['saml:sp:SessionIndex'] = $sessionIndex;
 $state['PersistentAuthData'][] = 'saml:sp:SessionIndex';
 $state['saml:sp:AuthnContext'] = $assertion->getAuthnContext();