On this date in 211AD, Septimius Severus choked on his last cookie, leaving the empire to his two sons, the brothers Geta and Caracalla.
Severus had been, on balance, a mediocre emperor. Suspicious to the point of paranoia, he had job lots of senators whacked for conspiracies both real and imaginary, and elevated fawning toadies to replace them. Similarly, he had no head for finance, and could be talked by his buddies into doing all manner of silly things, like appointing them Praetorian Prefect.
On the other hand, he knew which end of the spear got stuck in the barbarian, and he kept the heathens on the right side of their rivers, and when the woad-wearing savages north of the wall got uppity, he administered them a stomping, too. And he was popular with the plebs and those aristocrats he didn't decapitate because he possessed the charming quality of Not Being Commodus, a trait that was very much appreciated in Rome at the time.
History will judge him harshly, though, because he either had some demons lurking in his Y chromosome or he was a lousy parent. His younger son, Geta, was merely petulant and greedy, but that's to be expected from one raised to the purple. Geta's elder sibling, Caracalla, however, was a poisonous toad as psychotic as a Julio-Claudian on a bad hair day. He barely waited for dad's corpse to cool before having his brother iced by soldiers while in their mother's arms, and his conduct got worse from there to the point where he was finally shivved in the liver by one of his own bodyguards while answering nature's call along the roadside.
EDIT: After writing this, I discovered that I had discussed it last year as well. I can't help it; it's just such a colorful bit of history. Especially the "having your brother whacked in your mom's condo" part. That demonstrates some serious issues, you know?