Between 1346 and 1349, the Black Death killed almost half of the inhabitants of Constantinople. The city was further depopulated by the general economic and territorial decline of the empire, and by 1453, it consisted of a series of walled villages separated by vast fields encircled by the fifth-century Theodosian Walls.
Sultan Murad II laid siege to Constantinople in 1422, but he was forced to lift it in order to suppress a rebellion elsewhere in the empire. In 1444 he lost an important battle to a Christian alliance in the Balkans and abdicated the throne to his son, Mehmed II. However, he returned to power two years later after defeating the Christians and remained sultan until his death in 1451.