President Biden’s apparent confusion at campaign events is making headlines, with the GOP releasing videos every time he wanders away from world leaders or seems to shake an imaginary hand.

Democrats respond by attacking Donald Trump as less than mentally fit, mocking his odd conversational rambles into questions like whether it would be better to be electrocuted or eaten by a shark.

But questions about the mental competence of America’s 2024 presidential candidates pale in comparison to the men who once led the world’s greatest empire.

Some who ruled ancient Rome were real doozies. There was Commodus, who was so obsessed with gladiators that he hopped into the arena and fought hundreds of times before ultimately renaming Rome after himself. Tiberius was so depraved, he was the kind of guy who makes trouble in public parks. And let’s not forget Nero, who, though he didn’t fiddle as legend tells us, did jump onto a stage and belted out several songs while Rome burned around him.

But for sheer, outright insanity, none of them could hold a candle to Caligula, the most mentally unstable of the bunch.

How crazy are we talking? Instead of sleeping at night like normal people, he paced the halls of his palace talking out loud to the moon and Jupiter like they were his best friends. And that’s just for starters.

Barely 24 when he came to power in A.D. 37, Caligula had people executed on a whim and took the wives of prominent senators as his concubines (giving them no say about it).

Then there was the matter of his horse. Caligula apparently said something snarky about making his favorite horse a senator or proconsul. Both were top jobs in the Roman Empire. The story was repeated so relentlessly that some historians claim he actually did appoint the animal, though the evidence of that happening is shaky. Still, the incident became a metaphor for the emperor’s repeated promotion of grossly incompetent men to high public office.

Sadly, there are many more examples that, to put it mildly, show Caligula wasn’t playing with a full deck. Like when he declared war on the ocean.

No, really. It happened.

In the spring of A.D. 40, Caligula wanted to add Britannia (modern Great Britain) to the Roman Empire. But there was a problem. Some of the soldiers he assembled to conquer the island didn’t want to do it. There were at least two mutinies — bad ones — among the legion he had assembled for the invasion. That infuriated the young emperor. So he took out his anger by declaring war on Neptune, the god of the sea.

The Centurions arrayed along the English Channel in what’s now northern France faced a dilemma. They had very real orders to fight against an imaginary god. What to do?

Suetonius, biographer of the first 12 Roman emperors, described what came next.

“He drew up his army on the shore of the ocean, with his ballistas (catapults) and other war machines. And while no one could imagine what he intended to do, he suddenly commanded them to gather up seashells and fill their helmets and the folds of their tunics with them, calling them ‘the spoils of the sea.’”

With that, the emperor declared victory and went home. Caligula 1, Neptune 0.

Why did he do it? There are three theories.

The first says Caligula wanted to humiliate his soldiers for the mutinies. If that was the case, making them look like idiots for battling the ocean was a good way of shaming them.

According to theory No. 2, Caligula figured that even though he didn’t seize Britannia as he had said he would do, hauling all those shells back to Rome would make the good citizens believe he had accomplished something while away. (Britannia would eventually come under Roman rule during the reign of Claudius, his successor.)

Finally, theory No. 3 holds Caligula was just plain crazy. And there’s much validity to that view.

Whatever the reason, the ruling elite had finally had enough of the young ruler. He’d managed to infuriate everyone during his brief time on the throne. And one thing about those ancient Romans — you didn’t want them to get mad at you.

The following year, two tribunes joined by several Centurions hacked Caligula to death. His four-year run of craziness at the pinnacle of the Roman Empire was over.

Sure, Joe Biden and Donald Trump may have their share of “senior moments” that make them seem out of touch at times. But neither ever took on the ocean.

And Neptune and his mermaids have enjoyed uninterrupted peace in the 2,000 years since their one brief war, too.