The Ottoman domain shrinks drastically after Bayazid's defeat and capture by Timur in 1402. The many small emirs of Turkey reassert their independence, as do the Balkan states. The three sons of Bayazid are left with only the family's central territories round the southern and western sides of the sea of Marmara. They fight each other in a civil war which is won by the youngest, Mehmed I, in 1413. From this unpromising position, the son and grandson of Mehmed (Murad II and Mehmed II, whose combined reigns span nearly seventy years) achieve an astonishing recovery for the Ottoman state - posing an ever greater threat to the Byzantine empire.
Murad patiently reasserts control over much of western Anatolia, and makes equivalent headway in the Balkans. Serbia is brought back into the Ottoman fold (Murad marries a Serbian princess in 1433). Much of Bulgaria also is recovered. A strong counter-attack down the Danube in 1443 by an army of Hungarians and Poles is at first successful, until the Ottoman Turks win a decisive victory at Varna in 1444.
This steady process is continued by Murad's son, Mehmed II.
Mehmed II conquers Athens and almost the whole of the Greek peninsula in 1458-60. He then engages in a prolonged war with Venice, winning many valuable ports along the Adriatic coast. In 1463-4 he captures Bosnia where a large number of nobles convert to Islam, unlike neighbouring Serbia which remains largely Greek Orthodox - a distinction with resonance in more recent history. By the time of Mehmed's death, in 1481, Anatolia has also been recovered. Even regions north of the Black Sea are vassal states.
But the achievement which gives Mehmed his title of Fatih (Conqueror), and his secure place in history, has been his capture in 1453 of Constantinople.
Fall of Constantinople: AD 1453
A month after his twenty-first birthday, in April 1453,...