I have this framed because of the sundogs-- page CCIII from the German edition of Hartmann Schedel's Nuremberg Chronicle, printed by Anton Koberger in Nuremberg, Germany, in December of 1493.
This is the type of interest that makes ancient numismatics so much fun! We don't know everything and can think about the history and meaning of the types. Not once in this tread have we had to worry about whether the examples shown were MS62 or MS63.
I really enjoyed this post. It was informative and lucid. In my small LRB collection there are 2 SOLI INVICTO COMITI issues of Constantine, both from Rome. The "314" date of my attribution probably came from Wildwinds. Constantine I Follis (Æ 20) (314 A.D.) Rome mint IMP CONSTANTINVS PF AVG, laureate, cuirassed bust rt. / SOLI INV-I-CTO COMITI, Sol standing left in chlamys holding globe and raising right hand. R-F across; R*T. RIC VII Rome 20. (3.30 grams / 20 mm)
SEVERUS ALEXANDER AR Denarius OBVERSE: IMP ALEXANDER PIVS AVG, laureate, draped and cuirassed bust right REVERSE: P M TR P X COS III P P, Sol, radiate. standing left with raised hand and globe Struck at Rome, 231 AD 3.4g, 20mm RIC 109
A western Sol type paired with a Mars type, both from Trier, dating 310 to early 312: These seemed available enough 5 years ago but nowadays not so much.
My summary of Weiss's arguments posted on Forum in 2007: I agree with Jochen that a fundamental advance in this question was made by Peter Weiss, The Vision of Constantine, Journal of Roman Archaeology 16, 2003, 237-259. The vision in the sky, Weiss contends, was a solar halo, which appeared to Constantine and his army as he was marching north to counter a barbarian invasion on the Rhine after eliminating Maximian at Marseilles early in 310, and which is described in a Latin panegyric delivered before Constantine later in that year. Constantine interpreted this vision as a promise of victory from the sun god, explaining the sudden emergence of Sol as the chief god on his coinage from 310 on. In 312, there was no repeated heavenly vision, but Christ told Constantine in a dream that the sign he had seen in the sky two years earlier was Christ's sign, not Sol's, and he should put it on the shields of his soldiers before the impending battle with Maxentius. The victory over Maxentius convinced Constantine of Christ's sponsorship, as he states himself in his Letter to the Provincials of the East in 324: he calls upon the Greatest God to end the sufferings of the people of the East, not a vain request, "For under Thy guidance did I begin and bring to completion my salvation-bringing tasks. Carrying Thy Holy Sign before me everywhere, I have led the army to glorious victories....Truly because of this I have consecrated to Thee my own soul...." Why has this simple course of events, with two sudden revelations and changes of devotion by Constantine, not been seen by previous scholars? First because the language of the panegyric is complicated, and needs very careful reading and comparison with Eusebius' description of the heavenly vision. And second because Eusebius' account seems to compress the events of two and a half years into a single day, as though Constantine and his army saw the vision one afternoon and that very night Constantine had the dream instructing him to place the sign on the shields of his soldiers.
The appearence of the sign was commemorated in 350 in Vetranio's issues from Siscia: ' In hoc signo victor eris ' Perhaps this date 350 is not so random, but exactly 40 years after the first event in a string. Then 310 would fit in nicely with Sol appearing as a continuation of what Heliogabalos (= Elagabalus) imported from the East.