“Beware the Ides of March” is advice Rome gave the world, and the world has spent two thousand years testing whether it applies only to the original recipient. The evidence is mixed. March 15 has not always been violent. But it has, with some regularity, been the day someone discovers that the position they thought they held has already been vacated. On March 15, 44 BC, Gaius Julius Caesar arrived at the Theatre of Pompey for a meeting of the Senate and was stabbed twenty-three times by a group of senators who believed they were saving the republic.