The Ottoman state considered itself to be the "protector of the ideal world order (nizâm-ı âlem)" and the center of justice. As part of this view, the Sublime Porte assumed a regulatory role towards what it regarded as the peripheral elements (such as heterodox communities, or tribal and nomadic groups) of the provincial population of the Balkans, Anatolia, and the Arab lands. In the 19th century era of reforms, adopting the ''rational order'' and ''progress'' values of the European Enlightenment led to an even further enhancement of this role. Over the 17th and 18th centuries, on the other hand, the provinces had been governed by local gentry and notables enjoying a de facto autonomy. Thus after 1774, the centralizing and regulatory policies of reforming governments created new tensions between the center and the provinces. These tensions continued well into the late 19th century. This course aims to discuss this complex relationship between the center and peripheral populations from the 15th and 16th centuries onward, focusing on topics such as the New Order (Nizâm-ı Cedîd) reforms, Mahmud II's policies of centralization and provincial resistance, the issue of frontier regions (Bosnia, Albania, Kurdistan), the problem of the sedentarization of tribal/nomadic populations, and ideological steps to integrate peripheral groups into the imperial framework (the Hamidian era and the Second Constitutional Period).