Isaac II

Isaac II Angelos became Byzantine Emperor in 1185 by accident. He killed a royal official who had come to arrest him, the Constantinople mob took this as a rallying cry, and within hours the sitting emperor had fled and Isaac found himself crowned in the Hagia Sophia. He had not planned any of it. This was not an auspicious beginning, and it turns out it was a reasonably accurate preview of everything that followed.

The empire Isaac inherited was already fracturing at the edges. Bulgaria broke free on his watch in 1185, establishing the Second Bulgarian Empire after the brothers Asen and Peter led a rebellion he couldn't suppress. He fought off a Norman invasion from Sicily, which should have been a triumph, but his court was so riddled with corruption and his treasury so aggressively looted — often by Isaac himself, who had a weakness for elaborate weddings and golden baubles — that the victories never translated into stability. What he spent on his own coronation regalia alone reportedly scandalized the bureaucrats who had to account for it. He married the twelve-year-old daughter of the Hungarian king in 1185, a union that produced his eventual heir but little else of warmth.

In 1195, while Isaac was on campaign, his own brother Alexios III staged a coup. Isaac was captured, blinded with hot irons — the Byzantine method of rendering a rival ineligible for the throne — and locked in a Constantinople prison with his teenage son. And here is where it gets genuinely strange. That son, also named Alexios, escaped prison, made his way to Western Europe, and talked the leaders of the Fourth Crusade into redirecting their entire expedition to Constantinople to restore his father. In the summer of 1203, a crusading fleet appeared in the Bosphorus and Isaac II, blind and probably bewildered, was pulled from his cell and placed back on the imperial throne. He ruled again for less than a year before dying — possibly of shock, possibly of something more deliberate — in early 1204, just months before the Crusaders sacked the city his dynasty had failed to protect.