Albert II, 1397-1439, Holy Roman Emperor, king of Hungary and Bohemia (1438-39), duke of Austria (1404-38). He was the son-in-law of Holy Roman Emperor Sigismund, whom he aided against the Hussites of Bohemia. Albert was unable to suppress the Bohemian revolts (see Hussite Wars) and subsequently died on a disastrous campaign against the Turks. With Albert began the lasting Hapsburg rule over the Holy Roman Empire.