Stephen III of Moldavia

Stephen took refuge in Transylvania after his father Bogdan II was assassinated in 1451, then seized the Moldavian throne six years later at the Battle of Orbic with help from his cousin Vlad the Impaler. He spent the next decades playing Poland, Hungary, and the Ottoman Empire against each other - acknowledging suzerainty when cornered, then breaking free when the moment allowed. In 1475 he crushed a massive Ottoman invasion at Vaslui, earning Pope Sixtus IV's title "Champion of Christ," though no Western army ever came. The Ottomans took his key Danube ports in 1484; Stephen spent the rest of his reign trying to burn them back and bleeding Polish and Ottoman raiding parties in ambush battles through Moldavian forests. He built dozens of stone churches and fortresses, died in 1504 after forty-seven years in power, and left Moldavia with borders intact. The Romanian Orthodox Church canonized him in 1992.