Yet for all his power, Suleiman ultimately failed to carry the banner of Islam into the center of Europe. His siege of Vienna in 1529 ended in retreat. And although he vowed to return, he never did. Instead, he became consumed by the same sort of succession battles that had long undermined the Ottoman Empire; one of his four wives, Hurrem, claimed to have learned of a plot by Suleiman's first-born son and heir, Mustafa, to take over the throne. (Hurrem favored her own son, Selim II, for the sultanate.) Suleiman ordered Mustafa's execution and then descended into melancholy. He himself died in 1566, leaving the throne to Selim II, who soon squandered his legacy with sex and alcohol and left the empire to slowly crumble.
The center of global power would soon shift, as the Old World of Europe turned toward the New World across the Atlantic Ocean, eventually leaving the Ottomans in the historical dust. As a religion, Islam would continue to grow, to become the world's second-largest faith. But never again would it hold political or social dominion over the globe.