We don’t know for certain that anyone ever warned Julius Caesar to watch his back on the Ides of March.

We do know that the Greek historian, Plutarch, included a second-hand tale in his biography of Caesar about a seer warning the Roman leader to watch out during the first half of the famous month of lions and lambs.

According to Plutarch, the cocky Caesar snapped off a one-liner in the seer’s direction as he ambled toward the Senate chamber on the fateful morning of March 15, 44 BCE,

“Guess what, dude,” Caesar supposedly quipped. “The Ides are here, and so am I.” Or words to that effect.

To which, if Plutarch had it right, the seer replied, “It ain’t over till it’s over.” Or words to that effect.

We don’t know for certain that this clever bit of gallows badinage actually took place. But Plutarch’s version was enough to convince a certain British actor-writer named Shakespeare, who cribbed the entire account almost verbatim 643 years later.

In Act I, scene 2 of his play about why the emperor should have stood in bed (as they say), Caesar was strolling toward the Senate when a shrill voice hollered out from the crowd (which was a yuge crowd, probably the biggest crowd ever), “Beware the Ides of March.”

Caesar turned to his pal, Brutus, and said, “Who’s that guy? Is he one of ours?”

To which Brutus basically responded, “He’s just a kook. A soothsayer. Fake news. Forget about it.” Or words to that effect.

Mind you, we don’t know for certain that anyone named Shakespeare ever existed, let alone writing all those sombre comedies and thigh-slapping tragedies. According to some scholars, Shakespeare was merely a character invented by Christopher Marlowe. Or Francis Bacon. Or Mel Brooks.

For my historical reconstructions, I prefer good old, reliable Canadian sources such as Johnny Wayne and Frank Schuster. On May 4, 1958, they set the record straight for all time in their first-ever appearance on the Ed Sullivan Show.

In a sketch called “Rinse the Blood Off My Toga,” these heavyweight Toronto wise-guys revealed that it was neither seer nor soothsayer whose warnings fell on deaf imperial ears that day. It was Calpurnia (aka Mrs. Caesar) who sounded the alarm.

With her impassioned repetition of the line, “I told him, ‘Julie, don’t go,’” actress Sylvia Lennick earned a berth in both Canadian comedy and historical scholarship that Sunday evening.

I know. I saw it live, and became a believer. Not one year since have I ventured outside the house on the Ides of March. And I certainly don’t go anywhere near the Senate.