Have you ever heard the expression “crossing the Rubicon”? I have, but until this week I had no idea what it meant.
I was preparing to tutor Julius Caesar and wanted to understand the play’s opening, when Caesar is leading a triumphant procession through Rome.
Shakespeare doesn’t dwell too much on the historical details here (much of his audience would know it already), but he gives a wide variety of commentary on Caesar and his defeat of the “sons of Pompey.” Some citizens hero-worship Caesar, and others are disgusted–angry–apprehensive (heard of Brutus?).
I started by trying to figure out who Pompey himself was, and the story got complicated quickly. You think our politics are a mess? Brutus was a literal backstabber.
Then I ran across mention of the Rubicon River. Turns out this river is one of the north-south dividers for Italy, along with the Arno River on the west side. Caesar, returning from Gaul, could not legally cross the Rubicon with his troops.

So what did he do?
He crossed the river.
With his troops. Supposedly he said, “The die is cast,” just before his fateful move.
Caesar’s insubordination was definitive and shaped the chain of events that led to the Roman Empire and his assassination.
So we’ve arrived back at Shakespeare. And we’ve gained a great expression for crossing the point of no return.
Or throwing down the gaunlet.
Maybe waving a red flag at a bull.
Is there an expression I’m forgetting?
As always, thanks for reading. I hope you’ve walked away richer! Comment, like, and share if you feel so moved!
If you want to read a precise historical account of Caesar’s river crossing at Mike Anderson’s Ancient History Blog, click here: