We don’t know where the word Ides comes from or why the Ancient Romans used plural words for singular dates. Thanks, Caesar.
Today is the Ides of March, when Julius Caesar was notoriously assassinated in 44BC. Shakespeare immortalized the date when his soothsayer warned in The Tragedy of Julius Caesar: “Beware the ides of March” (1.2.19). Both of these are true: Caesar was killed on March 15 and a seer, according to ancient historians, did caution him the Roman ruler about the date, though didn’t exactly say Shakespeare’s famous words. But why is this day called the Ides and if it’s just one day, why don’t we call it an Ide?