ante diem xiii kalendas maias

ludi Cereri continue (day 8)-- games in honour of the grain goddess Ceres, instituted by/before 202 B.C.

Cerealia -- the actual date of the Cerealia is uncertain, but it 'reenacted' Ceres' search for her daughter Proserpina, with apparently all participants and spectators dressed in white. The ludi being celebrated for the past week are obviously connected.

69 A.D. -- Vitellius is recognized as emperor by the senate in Rome