Ecclesia Ordinis Caelestis Templum Olympicus/Celestial Order and Temple of Olympus

Festival for Sol Invictus

December 25

(Roman) Ancient: VIII Kal. Jan.
The cult of Sol Invictus (Unconquered Sun) was a comparatively late (3rd cent. CE) arrival from the East (Syria). It became the chief imperial cult of the Roman Empire, until it was replaced by Christianity. In the old calendar the winter solstice (Bruma = shortest [day]) fell on Dec. 25, so this was the day on which Sol proved Himself to be yet unconquered. [OCD s.v. Sol; SFR 212]