diff --git a/lib/SimpleSAML/Session.php b/lib/SimpleSAML/Session.php
index 307ebedf494dbc63607baa79c8e1f5e0da396791..e4487eff2e27ae89ff50e434a347f8fe30597914 100644
--- a/lib/SimpleSAML/Session.php
+++ b/lib/SimpleSAML/Session.php
@@ -554,24 +554,6 @@ class SimpleSAML_Session {
 	}
 
 
-	/**
-	 * Retrieve the time the user was authenticated.
-	 *
-	 * @return int|NULL The timestamp for when the user was authenticated. NULL if the user hasn't authenticated.
-	 * @deprecated
-	 */
-	public function getAuthnInstant() {
-
-		if (!isset($this->authData[$this->authority])) {
-			/* Not authenticated. */
-			return NULL;
-		}
-
-		assert('isset($this->authData[$this->authority]["AuthnInstant"])');
-		return $this->authData[$this->authority]['AuthnInstant'];
-	}
-
-
 	/**
 	 * Retrieve the attributes associated with this session.
 	 *
diff --git a/modules/saml/lib/IdP/SAML2.php b/modules/saml/lib/IdP/SAML2.php
index e48b3eada12cff4175513ce28da4c1abbaacbbdb..148d04c530a0cea59153be48f702cbdd56207ea8 100644
--- a/modules/saml/lib/IdP/SAML2.php
+++ b/modules/saml/lib/IdP/SAML2.php
@@ -804,10 +804,6 @@ class sspmod_saml_IdP_SAML2 {
 
 		if (isset($state['AuthnInstant'])) {
 			$a->setAuthnInstant($state['AuthnInstant']);
-		} else {
-			/* For backwards compatibility. Remove in version 1.8. */
-			$session = SimpleSAML_Session::getSessionFromRequest();
-			$a->setAuthnInstant($session->getAuthnInstant());
 		}
 
 		$sessionLifetime = $config->getInteger('session.duration', 8*60*60);