ante diem xii kalendas octobres
- Mercatus — after the completion of the ludi Romani, a few days were given over to restocking the cupboards
- 480 B.C. — battle of Salamis (one reckoning)
- 356 B.C. — birth of Alexander the Great (one reckoning)
- 91 B.C. — death of the orator Lucius Licinius Crassus (one author of the Lex Licinia Mucia which aggravated Latin sentiments and contributed to the outbreak of the Social War)
- 19 B.C. — death of Publius Vergilius Maro (maybe)
- ca. 220 A.D. — martyrdom of Theodore, Philippa, and companions
