The later reign of Mahmud II proved extremely tumultuous for the Ottoman state and society. Facing external and internal threats to their authority and the empire’s territorial integrity, the Ottoman political elite in Istanbul launched an unprecedented agenda of institutional reform, centralization and military mobilization. In 1826, Mahmud II (r. 1808-1839) destroyed the Janissary Corps, a potential threat to his power and policies, and ordered the creation of a disciplined, European style army. By the mid-1840s, perhaps as many as 300,000 men in total had been pressed into the regular and reserve formations, with the drilling, marching, and parading uniformed soldiers a common sight in Istanbul and in many of the provinces. This figure represented more than one-tenth of all Muslim males and one-fourth of all men considered eligible for military service by contemporary Ottoman censuses, which makes the Ottoman military mobilization from the 1820s to the 1840s comparable to that of France during the Napoleonic Wars. Ottoman decision-makers and ideologues, who demanded absolute loyalty and sacrifice from their conscripts as well as other subjects, repeatedly presented the era’s armed conflicts as ones waged between the rightful “Islamic State” and “foreign infidels,” “enemies of Islam,” “heretics” (i.e. Bekta?i Janissaries) , or, in cases such as the war against Mehmed Ali Pasha of Egypt (g. 1805-1848), as against rebels who had taken up arms against their legitimate Islamic ruler and the caliph, Sultan Mahmud II. Ironically nicknamed the “infidel sultan” by his critics, Mahmud II continuously used Islamic symbols and propaganda to legitimize his actions and actively presented himself and his new regime as the rightful promoters and protectors of Sunni Islam. This paper aims to account for how Mahmud II and his ideologues articulated and legitimated their wars, institutional reforms and unprecedented mobilization of ordinary subjects via Islam. Secondly, it will also probe how various groups of Ottoman subjects responded to the state policies and discourse, which will help determine their effects and limits within the empire. The research is based on primary sources from the Ottoman Archives of the Prime Minister’s Office (sultanic opinions and decrees, memoranda and correspondence on various state affairs), manuscripts from Süleymaniye Library, and printed pamphlets, military manuals and codes published by the Mahmudian state.