ante diem iii idus januarias

Carmentalia begins (day 1) -- a two-day festival (with a three day break between the days) in honour of the deity Carmenta, who was possibly a goddess of both childbirth and prophecy.

49 B.C. -- Julius Caesar crosses the Rubicon (by another reckoning)

?? B.C. -- dedication of the Temple of Juturna in the Campus Martius

29 B.C. -- Octavian closes the doors of the Temple of Janus, signifying the Roman world was at peace