Why did the Ottoman Empire fall? | AskHistorians Archive Observer

First, I would like to clarify some assumptions in your initial post, which will help to explain some of the issues the Ottoman Empire faced during its decline. Number one:

the Ottoman Empire was this huge arabian country

The Ottoman Empire was, for the majority of its history, a large, multi-ethnic empire. Importantly, its dominant class was never Arab, but was Turkish, descendants of tribes who migrated from Central Asia to Anatolia and founded the predecessor states to the Ottomans. This multi-ethnic nature will become important later. Number two:

north west of the arabian peninsula

At its peak, the Ottoman Empire (if we include lands who were nominally under the suzerainty of the Sultan) extended from the border of Morocco all along the African coast of the Mediterranean, down into Egypt, across the Red Sea to the Arabian Peninsula, up through the Levant, including what is now Iraq, up into the Caucuses, all of Anatolia, and a significant portion of the Balkan Peninsula, including Greece.

These two factors made the administration of such an empire enormously difficult. With a variety of ethnic groups -- many of which were forcibly brought under the banner of the empire -- and a territory that spanned three continents, simply holding together the empire was a challenge. Institutional problems made this difficult as well, and together, alongside foreign involvement, these factors all contributed to the decline of the Ottomans as a great power.

While the Ottomans enjoyed a period of expansion and superiority through the 15th and mid-16th centuries, a series of events conspired which threatened Ottoman ascendancy in the 16th and 17th centuries. The Portuguese voyages of exploration opened up alternate trade routes to India and Asia, weakening the commercial power of the Ottomans, who controlled part of the overland routes. European coalitions scored several victories against the Ottomans in military conflicts -- Lepanto saw a great loss of Ottoman ships and experienced soldiers to the Holy League, and the end of the Great Turkish War in a European victory resulted in the first major loss of Ottoman European territory. A series of wars with Safavid Persia also taxed the empire's manpower and financial resources, and the expansion of Russia into the Black Sea presented another growing threat. The involvement of the Janissary Corps, elite infantry soldiers, in politics hampered government as well.

By the 1800s, Ottoman provinces were slowly falling out of Istanbul's orbit. The French under Napoleon conquered Egypt in 1798; Egypt was conquered by the Ottoman Empire in 1517 but remained difficult to control. The Ottomans eventually re-established control with Muhammad Ali as the ruler of Egypt; he would eventually be granted the position of khedive, hereditary ruler of an autonomous vassal state of the Empire. Uprisings began in the Balkans at the start of the 19th century in Serbia and Greece; the later would gain its independence in 1832 after French and British intervention. In the 1830s, the French began their conquest of the Regency of Algiers, another autonomous region of the Empire, ruled by Turkish governors who exercised nominal authority over the region. Istanbul made little effort to defend the province. At the same time, the Balkan principalities started to gain limited autonomy -- recognition of Serbia, Wallachia, and Moldavia as independent under Ottoman suzerainty came during the 1800s, and they gradually moved more and more towards independence.

The Crimean War illustrated the weakness of the Ottoman Empire in the post-Napoleonic Era. Russia was able to invade the Danubian provinces of the Ottoman Empire after a crisis over religious minority rights; France and Britain, desiring to maintain the balance of power and prevent Russian expansion, intervened to help the Empire halt the Russian invasion. While European intervention prevented a disastrous invasion, it did little to quell rising nationalism, which threatened to splinter the Empire from within. During this time, the Empire implemented a series of reforms known as the Tanzimat, which attempted to modernize and centralize administration.

By 1900, the Ottomans had been pushed back to Anatolia and the Levant. Serbia, Bulgaria, Romania, and Montenegro had all achieved various degrees of independence, Tunisia had become a French protectorate, and Egypt fell under British influence. The vastly weakened empire was in poor shape, and began to finally collapse in World War I, as its Arab subjects revolted with British aid. By the end of the war, conditions were dire and ripe for revolution -- the empire was occupied and partitioned by the Entente powers. After the Turkish War of Independence, which others are probably more qualified to address than myself, the Sultanate and Caliphate were formally abolished and the Republic of Turkey proclaimed.

In conclusion, the Ottoman Empire collapsed after centuries of decline, due to rising nationalism, administrative difficulties, and invasions by hostile foreign powers. While I focused mainly on military invasions and loss of territory in this explanation, it's worthwhile to note that a series of treaties established special political and economic privileges for Europeans in the Empire, and brought substantial European influence into the Ottoman economy. These factors should not be overlooked when examining foreign invasion, which included, in the Ottoman case, both direct military intervention and more subtle methods.