Had to click the link to get to the bit about Plutarch’s Lives and the mention of Caesar refusing a crown on that day. That’s referenced in Shakespeare’s play, as well as the name of the day itself in the first scene where Flavius and Marullus are chasing away crowds who had come to honor Caesar and to remove decorations on the images of Caesar, on “the feast of Lupercal”.
“Will you be my bvtt-boy on this most holy day?”
“Um..... no.”