If we’re going to do this, then we should do it right! Last Tuesday was July 12 in the Gregorian calendar. Shouldn’t we be using Caesar’s own calendar? I went looking and found a couple of calendar converters (I found a nice one here which also explains some of the problems and the Roman calendar conventions) and they all agree: a.d. IV Id. Jul. MMDCCLVIII a.u.c. equates to July 25, 2005. But then if I understand PA correctly, Caesar’s birthday celebrations were only shifted to the 12th after his deification. JC himself would have celebrated on the 13th (a.d.III Id. Jul.), which would be the 26th.

This also raises the question of just when Caesar really was born. Before he reformed the calendar it had slipped badly, by several months if I recall. So did he adjust the date of his birthday to correspond to the time he was actually born (like George Washington) or was he really born in the spring (or fall, depending) and just kept the kept the date?