ante diem iii idus octobres

Fontinalia -- a festival in honour of the divinity Fons, who presided over springs and wells; such sources of water were festooned with garlands for the occasion

54 A.D. -- death of the emperor Claudius, purportedly succumbing to a plate of poisoned mushrooms dished up by his niece/wife Agrippina; dies imperii of Nero (son of Agrippina)