In 922 the Bulgarian emperor Simeon I sent envoys to al-Mahdi to propose a joint attack on the Byzantine capital Constantinople with the Bulgarians providing a large land army, and the Arabs a navy. It was proposed that all spoils would be divided equally, with the Bulgarians keeping Constantinople and the Fatimids gaining the Byzantine territories in Sicily and South Italy. As a result of the Byzantine–Bulgarian war of 913–927, by 922 the Bulgarians controlled almost the whole Balkan peninsula but Simeon I's main objective to capture Constantinople remained out of his reach because he lacked a navy. Although the Byzantines and the Fatimids had concluded a peace treaty in 914, since 918 the Fatimids had renewed their attacks on the Italian coast.