Beginning in 1839 under Mahmud II, massive political, military, and social reforms took place in the Ottoman Empire, centered on westernizing practices as an attempt to stave off imperial weakening and collapse. Having spent centuries in slow decline, being forced to ally with European nations in order to succeed at war, several military and territorial losses, social turmoil, and economic ruin, numerous western experts were invited, institutions adopted, and various reforms begun within the empire. These reforms, collectively known as the Tanzimat, culminated in the creation of a constitutional monarchy in 1876 which ushered in two years of experimental republicanism. Said two years, however, were only thanks to a military coup under the auspices of reformist societies working within the army, having forced Abdulaziz to abdicate in favor of his brother Abdul Hamid II, who began his reign working with and within the new constitutional government.
However, said government attempted to limit the powers of the sultanate, infuriating Abdul Hamid and causing conflict with British foreign relations. He eventually acted directly against the reformists, their document, and their institution – the constitutional period was abolished, its leaders executed. The failure of the empire during the Russo-Turkish War aided this reversion to autocracy; the subsequent Greco-Turkish War (1877-78) only furthered it. Increasingly despotic and distrusting, the actions of the throne stirred greater and greater unrest within the populace. By 1908, the military, led by Young Turk (a liberalizing reform movement of the intelligentsia, themselves heavily educated from Tanzimat-founded universities), had had enough and carried out a bloodless coup, forcing Abdul Hamid’s capitulation. The constitution was reasserted.
The liberalizing policies of the reinstituted government, counter to the traditional conservative religiosity of much of the population, triggered a counter-revolution less than a year later – the sultan was returned to power, the parliament’s continuance left in question. A counter-counterrevolution occurred shortly thereafter, led by Young Turk army officers and, notably, Mustapha Kemal. Now 1909, the restored parliament acted to remove the sultan from political, religious, and figurehead power, replacing him in each position as well as his vizier. Even this political upheaval did not stop the crumbling of the empire: territorial annexations during the previous decades remained in foreign hands and the Italio-Turkish War (1911-12) and the subsequent Balkan Wars (1912-13) shrank the empire and added further losses to the national psyche and war machine.
A secret treaty with the Germans coincidentally coupled with a nasty international naval incident entered the Ottomans into the Great War, almost happily for the British, who now had the means to open up a third front against the Central Powers. The Allies opted to invade the Gallipoli...