In the 19th century, the Ottoman Empire faced threats on numerous frontiers from multiple industrialised European powers as well as internal instabilities. Outsider influence, internal corruption and the rise of nationalism demanded the Empire to look within itself and modernize. Kickstarting a period of internal reforms to centralize and standardize governance, European style training regimens for the military, standardized law codes and reformed property laws were initiated to better collect taxes and control the resources within the borders. The period of these reforms is known as the Tanzimat, under the reign of the sultans Abdülmecid I and Abdülaziz, starting in 1839.

Despite the Ottoman empire's precarious international position, the central state was not strengthened. The process of reforming and modernization in the empire began with the declaration of the Nizam-I Cedid (New Order) during the reign of Sultan Selim III and was punctuated by several reform decrees, such as the Hatt-ı Şerif of Gülhane in 1839 and the Hatt-ı Hümayun in 1856. Over the course of the 19th century, the Ottoman state became increasingly powerful and rationalized, exercising a greater degree of influence over its population than in any previous era.

Despite these attempts at revitalisation, the empire could not stem the rising tide of nationalism, especially among the ethnic minorities in its Balkan provinces, where the newly implemented administrative and infrastructural reforms often intensified local tensions and nationalist movements rather than alleviating them. At the same time, neighboring Balkan states actively fostered separatism through schools, churches, and armed bands, particularly in contested regions like Macedonia, turning local society into a battleground of rival national projects. Numerous revolts and wars of independence, together with repeated incursions by Russia in the northeast and France (and later Britain) in the North African eyalets, such as Algiers, Tunis, and Tripoli (Tripolitania) resulted in a steady loss of territories throughout the 19th and early 20th centuries.

By 1908, the Ottoman military became modernized and professionalized along the lines of Western European armies. The period was followed by the defeat and dissolution of the Ottoman Empire (1908–1922).

Main issues of the period

The rise of nationalism, inspired in part by the French Revolution and the spread of romantic and liberal ideas across Europe, swept through many countries during the 19th century, and it affected territories within the Ottoman Empire, contributing to movements such as the Greek War of Independence and the Serbian Revolution. A burgeoning national consciousness, together with a growing sense of ethnic nationalism, made nationalistic thought one of the most significant ideas imported to the Ottoman Empire. The empire was forced to deal with nationalism from both within and beyond its borders. The number of revolutionary, secret societies which then turned into formal political parties—such as the Committee of Union and Progress emerging from the Young Turk movement and the Internal Macedonian Revolutionary Organization in the Balkans— during the next period rose dramatically.Uprisings in Ottoman territory had many far-reaching consequences during the 19th century and determined much of the Ottoman policy during the early 20th century. Much of the Ottoman ruling elite questioned whether the policies of the state were to blame: some felt that the sources of ethnic conflict were external and unrelated to issues of governance. While this era was not without some successes, the ability of the Ottoman state to have any effect on ethnic uprisings was seriously called into question.

The Russian extension in this century developed with the main theme of supporting the independence of the Ottomans' former provinces, and then bringing all of the Slav peoples of the Balkans under Bulgaria or using Armenians in the east to set the stage. At the end of the century, from the Russian perspective, Romania, Serbia, and Montenegro and the autonomy of Bulgaria were achieved. That alarmed the Great Powers. After the Congress of Berlin, the Russian expansion was controlled by stopping the expansion of Bulgaria. The Russian public felt that at the end of Congress of Berlin thousands of Russian soldiers had died for nothing.

The military of the Ottoman Empire remained an effective fighting force until the second half of the 18th century when it suffered a catastrophic defeat against Russia in the 1768-74 war. Selim III came to the throne with an ambitious effort for military reforms in 1789. He failed and was replaced by Mahmud II in 1808 who established martial law through Alemdar Mustafa Pasha. At first, he allied with the Janissaries to break the power of the provincial governors and then turned on the Janissaries and removed them altogether during the 1826 Auspicious Incident. Efforts for a new system (1826–1858) began following the Auspicious Incident.

Economic historian Paul Bairoch argues that free trade contributed to deindustrialization in the Ottoman Empire. In contrast to the protectionism of China, Japan, and Spain, the Ottoman Empire had a liberal trade policy, open to foreign imports.This policy had its origins in the capitulations of the Ottoman Empire, dating back to the first commercial treaties signed with France in 1536 and taken further with capitulations in 1673 and 1740, which lowered duties to 3% for imports and exports. The liberal Ottoman policies were praised by British economists such as John Ramsay McCulloch in his Dictionary of Commerce (1834), but later criticized by British politicians such as Prime Minister Benjamin Disraeli, who cited the Ottoman Empire as "an instance of the injury done by unrestrained competition" in the 1846 Corn Laws debate:

The Ottoman public debt loomed large during this period. The Empire had previously not taken foreign loans. But with the demands of the Crimean War, the Empire took its first loans in 1854 . The public debt quickly ballooned, becoming larger than any other European nation's. The Panic of 1873 depressed the economy, and was followed by poor harvests. The Ottomans found themselves unable to repay the loans, and so defaulted on their debt in 1875. The Ottomans owed their loans to various European countries and their citizens, who were deeply upset at the failure of their investment and lobbied their governments to intervene. This effort became the Ottoman Public Debt Administration, which grew to become a major and independent arm of the Ottoman bureaucracy, whose sole goal was providing returns to European creditors.

The stagnation and reform of the Ottoman Empire (1683–1827) ended with the dismemberment of Ottoman Classical Army. The issue during the decline and modernization of the Ottoman Empire (1828–1908) was to create a military (a security apparatus) that could win wars and bring security to its subjects. That goal took multiple Sultans with multiple reorganizations during this period. At the end of this period, with the Second Constitutional Era in 1908, Ottoman military became modernized and professionalized in the form of European Armies.

Modernization 1808–1839 1808–1839 Mahmud II

Mahmud II had to deal with multiple issues inherited from generations past. These issues lasted all through his reign. Shortly, the Eastern Question with Russia, England, and France, and military problems arising from mutinous Janissaries and factious Ulema. He also faced numerous internal conflicts with Egyptians, Najdis, Serbians, Albanians, Greeks, and Syrians, and had administrative problems from rebellious Pashas, who would fain have founded new kingdoms on the ruins of the House of Osman.

Mahmud understood the growing problems of the state and the approaching overthrow of the monarchy and began to deal with the problems as he saw them. For example, he closed the Court of Confiscations, and took away much of the power of the Pashas. He personally set an example of reform by regularly attending the Divan, or state council. The practice of the sultan's avoiding the Divan had been introduced two centuries prior, during the reign of Suleiman I, and was considered to be one of the causes of the decline of the Empire. Mahmud II also addressed some of the worst abuses connected with the Vakifs, by placing their revenues under state administration. However, he did not venture to apply this vast mass of property to the general purposes of the government.

Serbs, 1810s In 1804 the First Serbian Uprising against Ottoman rule erupted in the Balkans, marking the beginning of the Serbian Revolution. Although initially the uprising was suppressed in 1813, the Serbian revolutionary movement resumed with the Second Serbian Uprising in 1815, led by Miloš ObrenovićĆirković, Sima M. The Serbs. Oxford: Blackwell Publishing, 2004, pp. 191–210..By 1817, when the revolution ended, Serbia was raised to the status of self-governing monarchy under nominal Ottoman suzerainty.L. S. Stavrianos, The Balkans since 1453 (London: Hurst and Co., 2000), pp. 248–250. In 1821 the First Hellenic Republic became the first Balkan country to achieve its independence from the Ottoman Empire. It was officially recognized by the Porte in 1829, after the end of the Greek War of Independence.

Greeks, 1820s

In 1814, a secret organization called the Filiki Eteria was founded with the aim of liberating Greece. The Filiki Eteria planned to launch revolts in the Peloponnese, the Danubian Principalities, and capital with its surrounding areas. The first of these revolts began on 6 March 1821 in the Danubian Principalities which was put down by the Ottomans. On 17 March 1821, the Maniots declared war which was the start of revolutionary actions from other controlled states. In October 1821, Theodoros Kolokotronis had captured Tripolitsa, followed by other revolts in Crete, Macedonia, and Central Greece. Tensions soon developed among different Greek factions, leading to two consecutive civil wars. Mehmet Ali of Egypt agreed to send his son Ibrahim Pasha to Greece with an army to suppress the revolt in return for territorial gain. By the end of 1825, most of the Peloponnese was under Egyptian control, and the city of Missolonghi was put under siege and fell in April 1826. Ibrahim had succeeded in suppressing most of the revolt in the Peloponnese and Athens had been retaken. Russia, Britain and France decided to intervene in the conflict and each nation sent a navy to Greece. Following news that combined Ottoman–Egyptian fleets were going to attack the Greek island of Hydra, the allied fleet intercepted the Ottoman–Egyptian fleet in the battle of Navarino. Following a week-long standoff, a battle began which resulted in the destruction of the Ottoman–Egyptian fleet. With the help of a French expeditionary force proceeded to the captured part of Central Greece by 1828.

The Greek War of Independence saw the beginning of the spread of the Western notion of nationalism, stimulated the rise of nationalism under the Ottoman Empire, and eventually caused the breakdown of the Ottoman millet concept. Unquestionably, the concept of nationhood prevalent in the Ottoman Empire was different from the current one as it was centered on religion.

The Auspicious Incident, 1826