ante diem xii kalendas apriles

• Festival of Mars continues (day 21)
• Quinquatrus continues (day 3) — originally a one-day festival with rites in honour of Minerva, by Ovid’s day it had been increased to five days, with the last four involving gladiatorial bouts
• 1766 — death of Richard Dawes (Classical scholar)

pridie idus martias

• Festival of Mars (day 14)
• Equirria — the second of two days of horse racing (the first was on February 27) dedicated to Mars; the reasons are obscure, but probably have something to do with preparing horses for the upcoming campaigning season
• 222 A.D. — Severus Alexander is given the title Augustus

ante diem v idus martias

• Festival of Mars (day 11)
• 222 A.D. — murder of the emperor Elagabalus
• ca. 263 A.D. — martyrdom of Heraclius
• ca. 300 A.D. — martyrdom of Thalus
• ca. 300 A.D. — martyrdom of Trophimus
• 1903 — birth of Ronald Syme (The Roman Revolution, among other seminal works)

ante diem vi idus martias

• Festival of Mars (day 10) …
• 241 B.C. — Romans are victorious against the Carthaginians in the naval battle of Aegusa, bringing the First Punic War to an end
• 15 A.D. — Tiberius becomes pontifex maximus
• ca. 172 A.D. — martyrdom of Alexander in Phrygia
• ca. 258 A.D. — martyrdom of Codratus of Corinth and companions