Note 259 — MENSIS APRILIS.
Reading edition
The letters an also appear in a fragment of a lost note in Esq. Mommsen quotes Ovid, Fasti, 4. 775, and Tibull. 2. 5. 81 for the idea of an annus pastorum beginning on this day. I can find no explanation of it, astronomical or other. Dion. Hal. 1. 88 calls the day the beginning of spring, which it certainly was not.