DP826745Susanna Forrest at Literary Hub:

Mazeppa is one of Lord Byron’s later works, written just a few years before his death and shortly after he had fled England with scandal on his heels and debt dragging at his ankles. His wife had left him, taking their daughter with her. His lovers were numerous and garrulous. Rumor accused him both of homosexual affairs and of an incestuous passion for his half sister. Mazeppa—funnily enough—is about a delirious dash into exile, undertaken reluctantly but transforming its subject into a hero. Within three years of publication, Byron’s publisher John Murray had sold an impressive 7,400 copies.

Byron found his protagonist in Voltaire’s History of Charles XII, King of Sweden. The real historical Ivan Mazepa (Byron added the extra “p”) was a Cossack leader famous for defecting from Russia to Sweden before the 1709 Battle of Poltava. In Ukraine he is still a hero, in Russia, a villain. According to Voltaire, as a young man in the 1660s he served as a page at the court of King John II Casimir in Poland but was caught cuckolding a noble who had him stripped naked, tied to a “wild horse” and thus dispatched all the way back to his Ukrainian homeland. The tall tale of his amorous escapades can be traced back to the memoirs of a courtier called Pasek who held a long-standing grudge against Mazepa. In Pasek’s account, when Mazepa is caught by the irate husband he’s strapped not to the back of a wild horse but his own tame saddle horse, which promptly scarpers back to its home stable via bramble patches. Voltaire upgraded the story. Byron took it further.

more here.