diff --git a/library/Zend/Date/DateObject.php b/library/Zend/Date/DateObject.php
index 32e76dbc93..9bb6879ae7 100644
--- a/library/Zend/Date/DateObject.php
+++ b/library/Zend/Date/DateObject.php
@@ -1019,12 +1019,7 @@ public function setTimezone($zone = null)
         }
 
         // throw an error on false input, but only if the new date extension is available
-        if (function_exists('timezone_open')) {
-            if (!@timezone_open($zone)) {
-                #require_once 'Zend/Date/Exception.php';
-                throw new Zend_Date_Exception("timezone ($zone) is not a known timezone", 0, null, $zone);
-            }
-        }
+        new DateTimeZone($zone);
         // this can generate an error if the date extension is not available and a false timezone is given
         $result = @date_default_timezone_set($zone);
         if ($result === true) {