The Greek campaign was launched primarily because the western Allies, particularly British Prime Minister David Lloyd George, had promised Greece territorial gains at the expense of the Ottoman Empire, recently defeated in World War I, as Anatolia had been part of Ancient Greece and the Byzantine Empire before the Ottomans captured the area. The armed conflict started when the Greek forces landed in Smyrna (now İzmir), on 15 May 1919. They advanced inland and took control of the western and northwestern part of Anatolia, including the cities of Manisa, Balıkesir, Aydın, Kütahya, Bursa and Eskişehir. Their advance was checked by Turkish forces at the Battle of Sakarya in 1921. The Greek front collapsed with the Turkish counter-attack in August 1922, and the war effectively ended with the recapture of Smyrna by Turkish forces and the great fire of Smyrna.