Suleiman the Magnificent developed the power of the Ottomanns to its greatest extent, he captured Belgrade, subjugated Hungary, besieged Vienna (1529) and conquered parts of North Africa. During the sixteenth century the Ottoman fleet made them masters of the Mediterranean.

The conquered territories were divided into military fiefs. The sultan began the practise of exacting an annual tribute of Christian children to provide a loyal corps of palace soldiers. The Janissary, as the new troops were called, soon became the terror of Europe. But the very strength of the Turkish military organisation led to inernal weakness. The slave army, numbering up to 100,000 men, became a state within a state. To protect themselves from palace coups, the reigning sultan confined his brothers to celibacy in walled gardens. As a result, when later sultans were succeeded by a brother, the fledling ruler was ignorant of his responsibility.

The first signs of the empires weakness became apparent during the Great Turkish War  (1683-99), which began with the second siege of  Vienna and ended with the transfer of most of Hungary from Ottoman to Austrian hands.

Gradually, portions of the empire began to break away. By 1850,  Egypt and Arabia gained autonomy, and  Algeria was controlled by France. In the Balkans Greece won independence in 1830. The Ottoman Empire which suffered a series of defeats by Austrian and  Russian armies, was reluctant to modernize its institutions because pious Muslims felt that the whole Islamic character of the state would be endangered.

The  Crimean War, where Ottomans were fighting together with French and British forces, ended with a victory over the Russians. Ironically, the victory cost the Turks more than earlier defeats at Russinas hands had ever done, because it became clear that the survival of the Ottoman empire depended on the support of one or another of the European Great powers.
Britain and France had an interest to prevent the collapse of the Turkish empire because they considered it a block against the expansion of Russia or Austria into the Balkans. Until the 1870's Great Britain played the role of primary protector of the Sultan; later the Germans played the same role.
The belated attempt of the sultan to modernize the army backfired in 1908 when young officers - the Young Turks - organized a coup d'etat. The political fortune of Islam reached their low point at the close of World War I when the Ottoman empire was partitioned among the victors. In 1923  Ataturk assumed power and proclaimed the Turkish Republic.