Sol Invictus

Sol invictus "the Unconquered Sun" is the name of a Roman sun (sol) god popular from at least the 3rd century.

Before Sol invictus came to prominence, the Romans already had a sun god, Sol indiges, who had been worshiped since the period of the Roman Republic. (The meaning of "indiges" is debated. Sol indiges could mean the indigenous sun.) The Emperor Nero had built a colossal statue associated with a sun god Sol.

Sol invictus may have been an import from the East. The Roman emperor Elagabalus worshiped a Syrian sun god, but it is Emperor Aurelian who is particularly associated with the invictus because he, having attributed to the god his victory over the Palmyrenes [see Table of Roman Battles], set up a temple to Sol invictus in the Campus Martius, established a priesthood for the god, and created games in his honor (ludi solis), in 274. Aurelian tried to establish Sol invictus as supreme god of the Romans, particularly among the military.

During the period of the tetrarchy, Jupiter and Hercules regained prominence in the Roman pantheon, but then, with the accession of Constantine, Sol invictus became top god until Rome's conversion to Christianity.

References:

• _{"New Evidence for the Dating of the Calendar at Santa Maria Maggiore in Rome"
  M. R. Salzman
  Transactions of the American Philological Association (1981), pp. 215-227}
  
• _{"'Good Emperors' and Emperors of the Third Century"
  Sviatoslav Dmitriev
  Hermes 2004), pp. 211-224}
  
• _{Official Policy towards Oriental Cults in the Roman Army
  Allan S. Hoey
  Transactions and Proceedings of the American Philological Association (1939), pp. 456-481}
  
• _{"The Gods of the Months in Ancient Art"
  Charlotte R. Long
  American Journal of Archaeology (Oct., 1989), pp. 589-595}
  
• _{"Framing the Sun: The Arch of Constantine and the Roman Cityscape
  Elizabeth Marlowe
  The Art Bulletin (Jun., 2006), pp. 223-242}
  

• _{"The Topography and Social History of Rome's Trastevere (Southern Sector)"
  Robert E. A. Palmer
  Proceedings of the American Philosophical Society, 1981}