Constantine is an emperor.
Constantine is a 2005 American-German occult detective action horror film directed by Francis Lawrence as his feature film directorial debut , starring Keanu Reeves as John Constantine , with Rachel Weisz , Shia LaBeouf , Tilda Swinton , Pruitt Taylor Vince , and Djimon Hounsou . Constantine the Great . As emperor , Constantine enacted many administrative , financial , social , and military reforms to strengthen the empire .