ante diem vi idus decembres

• Rites in honour of Tiberinus and Gaia — not a lot is known about these rites; Tiberinus had a temple on the Tiber island and presided over the Tiber (of course); Gaia seems to have originally given the Campus Martius (a.k.a. Campus Tiberinus) to the Roman people.
• 65 B.C. — birth of the poet Horace (Quintus Horatius Flaccus)

ante diem xii kalendas decembres

• Mercatus — time to restock the cupboards after the Jupiterfest!
• 63 A.D. — shipwreck of St. Paul (by one reckoning)
• 270 (?) — birth of the future emperor Maximinus Daia
• 284 A.D. — elevation of Diocletian to the rank of Caesar

ante diem xiv kalendas decembres

• Mercatus — in the wake of the lengthy ludi Plebeii, the Romans needed a few days to restock their cupboards
• ca. 64 A.D. — upside down crucifixion of Peter
• 303 A.D. — martyrdom of Hesychius of Antioch
• 1718 — premiere of Voltaire’s Oedipe in Paris