In 1515 Sigismund entered into an alliance with the Holy Roman Emperor Maximilian I. In return for Maximilian lending weight to the provisions of the Second Peace of Thorn (1466), Sigismund consented to the marriage of the children of Vladislaus II of Bohemia and Hungary, his brother, to the grandchildren of Maximilian. Through this double marriage contract, Bohemia and Hungary passed to the House of Habsburg in 1526, on the death of Sigismund's nephew, Louis II, who led his forces against Suleiman the Magnificent of the Ottoman Empire in the disastrous Battle of Mohács.