called Vlachs, such as the Bjelice or the Nikšići. The katun was primarily a kinship organization, but since the Vlach shepherds were also serving as soldiers, it was also a military organization. Thus, the župas were broken up by the katuns in areas where the katuns became tribes. In this case, whether through kinship, i.e., by bringing together unrelated people in an allegedly blood-related core group, or by uniting families without imposing a blood union, the Vlach katuns introduced elements of their kinship structure and military democracy into the tribes that arose on the ruins of the feudal territorial organization. Organization The tribes (plemena, ) were territorial and socio-political units composed of clans (bratstva, ) in historical Montenegro. The tribes are not necessarily kin as they only serve as a geopolitical unit. The tribes enjoyed especially large autonomy in the period from the second part of the 15th century until the mid-19th century. Initially they were recorded as katuns - a basic Albanian/Vlach social and ethnic structure not always homogeneous by blood on which head was katunar - tribal chief. With Slavicization, former katuns began to be called plemena (meaning both tribe and clan), while the katunar became Slavic vojvoda or knez. Following the Ottoman occupation, the relative isolation from one another and lack of centralized authority made them local self-governing units. The clans or brotherhoods (bratstvo) are made of patrilocal kin groups (rodovi, ) which usually trace their origin to a particular male ancestor and share the same surname. Names of brotherhoods are derived from either names, nicknames or profession of the ancestor. The bratstvo is an exogamous group and in most cases, marriage within the bratstvo is forbidden regardless of the biological distance between the would-be spouses. However, this is not the case with some larger brotherhoods who sometimes allow endogamous marriages if the genealogical distance between spouses is large enough. In war, the members of the bratstvo (bratstvenici) were obliged to stand together. The size of such units varied in size, ranging from 50 to 800 warriors (1893). Through time the bratstvo would split into smaller subdivisions and acquire separate names. Contemporary surnames of Montenegrins usually come from these smaller units. The members tend to guard their family history and many are able to recite the line of ancestors to the originator of the bratstvo. A tribe is commonly made up of several brotherhoods of different ancestry.