Sol Invictus ( `` Unconquered Sun '' ) was the official sun god of the later Roman Empire and a patron of soldiers .
Sol Invictus ( `` the Unconquered Sun '' ) or , more fully , Deus Sol Invictus ( `` the Unconquered Sun God '' ) was a religious title applied to at least three distinct deities during the later Roman Empire : El Gabal , Mithras , and Sol .