Vlasi / Власи) was a social and fiscal class in several late medieval states of Southeastern Europe, and also a distinctive social and fiscal class within the millet system of the Ottoman Empire, composed largely of Eastern Orthodox Christians who practiced nomadic and semi-nomadic pastoral lifestyle, including populations in various migratory regions, mainly composed of ethnic Vlachs, Serbs and Albanians.
[1][2] From the middle decades of the 17th century the amalgamation of the process of sedentarization of the Orthodox Vlachs and their gradual fusion with Serbian rural population reached a high level and was officially recognized by the Ottoman authorities.
[5] It thus propitiated special arrangements between the Turks and the Vlachs,[7] who in turn, while preserving their religion (excepting some, largely high-ranking members of society, who converted to Islam in order to secure for themselves and their families special privileges and prominent administrative positions from the Ottoman authorities), placed themselves in the Sultan's service;[5] all this made possible that the Vlachs would come to form a considerably privileged class within the Millet system in the Ottoman Empire, compared to the class of the Reaya, for more than a century.
In addition, they always accompanied the Ottoman armies in their expeditions throughout the Balkans, up to the North-West, in whole communities; being intended for populating the newly conquered territories as border military colonies, called katun or džemaat (which were composed of about 20 to 50 houses); at the head of which there was a katunar or primikur ("headman").
[5] At the same time, great Turkish and Slavic Muslim landholding military nobles (Sipahi and Timarli) often brought with them significant quantities of these Vlachs[12] (sometimes Serbs as well),[13] in order that they farmed their lands.