Aurelian
The Roman gens Aurelia was associated with the cult of Sol. After his victories in the East, the Emperor Aurelian thoroughly reformed the Roman cult of Sol, elevating the sun-god to one of the premier divinities of the Empire. Where previously priests of Sol had been simply sacerdotes and tended to belong to lower ranks of Roman society, they were now pontifices and members of the new college of pontifices instituted by Aurelian. Every pontifex of Sol was a member of the senatorial elite, indicating that the priesthood of Sol was now highly prestigious. Almost all these senators held other priesthoods as well, however, and some of these other priesthoods take precedence in the inscriptions in which they are listed, suggesting that they were considered more prestigious than the priesthood of Sol. Aurelian also built a new temple for Sol, bringing the total number of temples for the god in Rome to (at least) four He also instituted games in honor of the sun god, held every four years from AD 274 onwards.
The confusion surrounding Aurelian's reforms has been significant, much of it rooted in the mistaken opinion that he was introducing a new cult, which, as is now clear, he was not. The following constitute the most common errors of fact attributed to Aurelian and his reforms.
1. Aurelian called his sun god Sol Invictus to differentiate him from the earlier Roman god Sol.
Actually, Aurelian is twice as likely to call Sol Oriens on his coins as he is Sol Invictus. Only one of the fifteen or so pontifices of Sol adds the epithet invictus; all others simply call themselves "pontifex Solis".
2. Aurelian built his new temple for a Syrian sun god, not the Roman one.
There is no credible evidence to support this, and ample evidence to refute it. The "Syrian Sol-hypothesis" is therefore now rejected by all specialists in the field.
3. Aurelian inaugurated his new temple dedicated to Sol Invictus and held the first games for Sol on December 25, 274, on the supposed day of the winter solstice and day of rebirth of the Sun.
This is not only pure conjecture, but goes against the best evidence available. There is no record of celebrating Sol on December 25 prior to AD 354/362. Hijmans lists the known festivals of Sol as August 8 and/or 9, August 28, and December 11. There are no sources that indicate on which day Aurelian inaugurated his temple and held the first games for Sol, but we do know that these games were held every four years from AD 274 onwards. This means that they were presumably held in AD 354, a year for which perchance a Roman calendar, the Chronography of 354 (or calendar of Filocalus), has survived. This calendar lists a festival for Sol and Luna on August 28, Ludi Solis (games for Sol) for October 19–22, and a Natalis Invicti (birthday of the invincible one) on December 25. While it is widely assumed that the invictus of December 25 is Sol, the calendar does not state this explicitly. The only explicit reference to a celebration of Sol in late December is made by Julian the Apostate in his hymn to King Helios written immediately afterwards in early AD 363. Julian explicitly differentiates between the one-day, annual celebration of late December 362 and the multi-day quadrennial games of Sol which, of course, had also been held in 362, but clearly at a different time. Taken together, the evidence of the Calendar of Filocalus and Julian's hymn to Helios clearly shows, according to Hijmans and others, that the ludi of October 19–22 were the Solar Games instituted by Aurelian. They presumably coincided with the dedication of his new temple for Sol.
4. After Aurelian, Sol became supreme deity of the Roman Empire.
(Hijmans 2009, chapter 9) raises serious doubts about this contention.
Read more about this topic: Sol Invictus