Ivan III of Russia
Matthias Corvinus had Vlad the Impaler, Voivode of Wallachia, imprisoned for allegedly conducting secret negotiations with the Ottoman Empire in 1462, and only released him in early 1475. Fyodor Kuritsyn, who was the ambassador of Ivan III of Russia to Corvinus in the early 1480s, recorded that Corvinus had given his "sister" in marriage to Vlad and they had lived together for ten years. Hassan concluded that Kuritsyn obviously combined data about Vlad's two wives when writing his report. Vlad's first wife was most probably Corvinus' illegitimate sister, according to modern scholarly research, who died in either 1472 or 1473.