the late 17th century, most intensively between mid-18th century and the 1840s they seem to have moved eastwards. The migrating parts of tribes maintained a tribal outlook and household structure. A 1930s Serbian study by Atanasije Urošević estimated that 90% of Kosovo Albanians in particular areas of eastern Kosovo descended from these migrating tribes; most belonged to the Krasniqi, the rest to the Berisha, Gashi, Shala, Sopi, Kryeziu, Thaçi and Bytyqi tribes. Historian Noel Malcolm has criticized the Urošević study for its broad generalization to the whole of Kosovo, as it focused on Eastern Kosovo, while omitting Western Kosovo to reach those conclusions. Malcolm also noted that commonalities of Kosovo Albanian family names with Albanian clan names is not always indicative of having Albanian Malësi clan origins, as some people were agglomerated into clans while many other Kosovo Albanians lack such names. The study also revealed that the same population figures between older and newer settlement patterns were the same for the Serb population in eastern Kosovo as most had settled in the area in the last 200 years. Kosovo was part of the Ottoman Empire from 1455 to 1912, at first as part of the eyalet of Rumelia, and from 1864 as a separate province (vilayet). During this time, Islam was introduced to the population. Today, Sunni Islam is the predominant religion of Kosovo Albanians. The Ottoman term Arnavudluk (آرناوودلق) meaning Albania was used in Ottoman state records for areas such as southern Serbia and Kosovo. Evliya Çelebi (1611–1682) in his travels within the region during 1660 referred to the western and central part of what is today Kosovo as Arnavudluk and described the town of Vučitrn's inhabitants as having knowledge of Albanian or Turkish with few speakers of Slavic languages. Modern period 19th century A large number of Albanians alongside smaller numbers of urban Turks (with some being of Albanian origin) were expelled and/or fled from what is now contemporary southern Serbia (Toplica and Morava regions) during the Serbian–Ottoman War (1876–78). Many settled in Kosovo, where they and their descendants are known as muhaxhir, also muhaxher ("exiles", from Arabic 'muhajir'), and some bear the surname Muhaxhiri/Muhaxheri or most others the village name of origin. During the late Ottoman period, ethno-national Albanian identity as expressed in contemporary times did not exist amongst the wider Kosovo Albanian-speaking population. Instead collective identities were based upon either socio-professional, socio-economic, regional, or religious