Amburbium -- a 'moveable feast' which may or may not have actually been held on this day, but does seem to have happened near the end of February. A sacrificial procession was led around the boundaries of the city as a rite of purification.
509 B.C. -- During a major attempt by the expelled Tarquins to reclaim the throne of Rome, the consul Lucius Junius Brutus dies while engaged in single combat with Arruns Tarquin, who was also killed (according to one reckoning)
116 A.D. -- supplicatio pro salute Traiani (day 3)
1631 -- birth of Henry Stubbe (Greek and Latin scholar and author of a work which is rather timely today, it seems).