For all of his success, it was under the reign of Alexander I that the first confrontation with the Ottoman Turks took place at Cetatea Albă in 1420. A deep crisis was to follow Alexandrel's long reign, with his successors battling each other in a succession of wars that divided the country until the murder of Bogdan II and the ascension of Peter III Aaron in 1451. Nevertheless, Moldavia was subject to further Hungarian interventions after that moment, as Matthias Corvinus deposed Aron and backed Alexăndrel to the throne in Suceava. Petru Aron's rule also signified the beginning of Moldavia's Ottoman Empire allegiance, as the ruler agreed to pay tribute to Sultan Mehmed II.