After the death of John in 1540, he was succeeded by his one-month-old son, John Sigismund Zápolya. Ferdinand in 1541 tried to capture Buda, the capital, but he was defeated by Suleiman's army. The Ottoman emperor occupied Buda after the victory and sent the young Hungarian king with his court to Lippa (today Lipova, Romania); in 1542 they moved to Gyulafehérvár (today Alba Iulia, Romania), which later became the capital of the Principality of Transylvania.