Mahmud II in the context of "Abdülmecid I"

Ottoman Iraq or Hıtta-i Irakiyye (Ottoman Turkish: خطهٔ عراقیه, romanized: Hıṭṭa-i ʿIrāqiyye, lit. the Iraq region) was the Ottoman name for the region of Iraq that was under their control. Historians often divide its history into five main periods. The first began with Sultan Süleyman I's conquest in 1534 and ended with the Safavid capture of Baghdad in 1623. The second lasted from the Ottoman reconquest in 1638 to the start of Mamluk self-rule in 1749. The third period, from 1749 to 1831, was marked by the Georgian Mamluk dynasty’s semi-autonomous governance. The fourth stretched from the Ottoman removal of the Mamluks in 1831 to 1869, when reformist governor Midhat Pasha took office. The fifth and final phase ran from 1869 until 1917, when British forces occupied Baghdad during the First World War.

Administratively, during the first period in the 16th century, Baghdad Eyalet encompassed much of the territory of modern Iraq. In the 17th century, the Ottomans had reorganized Iraq into four eyalets (Baghdad, Basra, Mosul, and Shahrizor). However, from the late 17th century, a trend of administrative unification began, with Basra coming under Baghdad's control from around 1705 and Mosul and Shahrizor following after 1780 during the semi-autonomous Mamluk period. Following this unification, Mamluk rulers such as Sulayman the Great were described as governing “all of Iraq”, and the Ottomans themselves began referring to the region unofficially as “the land of Iraq”. By 1830, and possibly earlier, these were being collectively referred to in official Ottoman correspondence as the region of Iraq, as attested in a letter from Sultan Mahmud II. The four eyalets were later consolidated in the 19th century into the vilayets of Mosul, Baghdad, and Basra, collectively referred to in official Ottoman documents as the Iraq Region (Hıtta-i Irakiyye).

The Ottoman army was the military structure established by Mehmed II (r. 1451–1481) during his reorganization of the Ottoman state and its military. It resulted from a major reorganization of the standing army dating from the time of Sultan Orhan (r. 1323/4–1362), which had centred on janissaries who were paid by salary rather than rewarded with booty or fiefs. The army built by Orhan had operated during the period of the rise of the Ottoman Empire (1299 to 1453).

The organization introduced by Mehmed II was twofold, central (Ottoman Turkish: Kapıkulu, the household division) and peripheral (Ottoman Turkish: Eyalet, province-level). Sultan Mahmud II forced this army to disband on 15 June 1826 in what is known as Auspicious Incident, which followed a century-long reform effort.

Abdulaziz (Ottoman Turkish: عبد العزيز, romanized: ʿAbdü'l-ʿAzîz; Turkish: Abdülaziz; 8 February 1830 – 4 June 1876) was the sultan of the Ottoman Empire from 25 June 1861 to 30 May 1876, when he was overthrown in a government coup. He was a son of Sultan Mahmud II and succeeded his brother Abdulmejid I in 1861.

Abdulaziz's reign began during the Ottoman Empire's resurgence following the Crimean War and two decades of the Tanzimat reforms, though it was now reliant on European capital. The decade after his ascension was dominated by the duo of Fuad Pasha and Aali Pasha, who accelerated reorganization of the Empire. The Vilayet Law was promulgated, Western codes were applied to more aspects of Ottoman law, and the millets were restructured. The issue of Tanzimat dualism continued to plague the empire, however.

Starting in the 19th century the Ottoman Empire's governing structure slowly transitioned and standardized itself into a Western style system of government, sometimes known as the Imperial Government. Mahmud II (r. 1808–1839) initiated this process following the disbandment and massacre of the Janissary corps, at this point a conservative bureaucratic elite, in the Auspicious Incident. A long period of reform known as the Tanzimat period started, which yielded much needed reform to the government and social contract with the multicultural citizens of the empire.

In the height of the Tanzimat period in 1876, Abdul Hamid II (r. 1876–1909) turned the Empire into a constitutional monarchy by promulgating the Empire's first Constitution, which established the short First Constitutional Era and also featured elections for a parliament. Defeat in the 1877–1878 War with Russia and dissatisfaction with Abdul Hamid lead to the "temporary" suspension of the constitution and the parliament, resulting in a modern despotism/autocracy of Abdul Hamid, during which internal reform continued. The Young Turk Revolution in 1908 started the longer lasting Second Constitutional Era and forced Abdul Hamid to reinstate the constitution, recall the parliament, and hold elections again which this time which featured political parties. However, by 1913 the Ottoman Empire was a dictatorship of the Committee of Union and Progress (CUP), led by the Three Pashas (Talat Pasha, Enver Pasha, and Cemal Pasha). This dictatorship capitalized on the developed bureaucracy created through a century of reform and centralization by undertaking genocide against Christian minorities. The CUP also undertook many reforms relating to social structure, religion, and education, which would be continued and more far reaching under Mustafa Kemal Atatürk's regime. The Union and Progress dictatorship lasted until the end of World War I, which lead to the Empire's collapse and subsequent abolition by Turkish nationalist forces led by Atatürk.

A janissary (UK: /ˈdʒænɪsəri/ JAN-iss-ər-ee, US: /-sɛri/ -⁠err-ee; Ottoman Turkish: یڭیچری, romanized: yeñiçeri, IPA: [jeˈŋit͡ʃeɾ̞i], lit. 'new soldier') was a member of the elite infantry units that formed the Ottoman sultan's household troops. They were the first modern standing army, and perhaps the first infantry force in the world to be equipped with firearms, adopted during the reign of Murad II (r. 1421–1444, 1446–1451). The corps was established under either Orhan or Murad I, and dismantled by Mahmud II in 1826.

Janissaries began as an elite corps made up through the devşirme system of child levy enslavement, by which Christian boys, chiefly from the Balkans, were taken, levied, subjected to forced circumcision and forced conversion to Islam, and incorporated into the Ottoman army. They became famed for internal cohesion cemented by strict discipline and order. Unlike typical slaves, they were paid regular salaries. Forbidden to marry before the age of 40 or engage in trade, their complete loyalty to the Ottoman sultan was expected. By the 17th century, due to a dramatic increase in the size of the Ottoman standing army, the corps' initially strict recruitment policy was relaxed. Civilians bought their way into it in order to benefit from the improved socio-economic status it conferred upon them. Consequently, the corps gradually lost its military character, undergoing a process that has been described as "civilianization".

The Slaughter of the Knezes (Serbian: Сеча кнезова, romanized: Seča knezova) was a campaign of organized murders and assaults of notable Serbs in the Pashalik of Belgrade (Sanjak of Smederevo) by the renegade Janissaries who had seized power in a coup against the Ottoman Sultan Mahmud II. Fearing Serbian plans of rebellion, they decided to execute leading Serbs throughout the Sanjak. At least 95 notable Serbs were murdered, many whose decapitated heads were put on public display. Notable victims were Aleksa Nenadović and Ilija Birčanin. The event triggered the First Serbian Uprising, aimed at putting an end to the centuries of Ottoman occupation.