The name Kosovo (as referred to in this spelling) is the most frequently used form in English when discussing the region in question. The Albanian spelling Kosova has lesser currency. The alternative spellings Cossovo and Kossovo were frequently used until the early 20th century. Terminology The toponym Kosovo in contemporary times refers to entire territory of Kosovo. Kosovo originally referred to plain of Kosovo, which forms part of eastern Kosovo. Regions which are today considered parts of Kosovo include Dukagjin/Metohija, Llapusha, Llap and other areas. Kosovo was used as the name of the entire territory for the first time in 1877 when the Kosovo Vilayet was created by the Ottoman administration. In antiquity Dardania There is a theory within linguistics that the name Dardania used in ancient times for the area of Kosovo is derived from the Albanian word dardhë, meaning "pear". Due to its Slavic (Serbian) character, Kosovo Albanian leader Ibrahim Rugova supported a name change to "Dardania", in reference to the ancient kingdom and later-turned Roman province. It, however, did not enter into general usage. Medieval and contemporary Kosovo Kosovo () is the Serbian neuter possessive adjective of kos (), meaning "blackbird"; -ovo being an adjectival suffix – it is short for the region named the "field of the blackbird" (), the Kosovo Field, the site of the 1389 battle between the army of Serbian Prince Lazar and the Ottoman Army, which ended in an Ottoman victory and Serbian decline. The name Kosovo Kos- is found in hundreds of Slavic locations. The cognate of Proto-Slavic kosь is Ancient Greek κόσσυφος. Linguistic and historical research have shown that the medieval Serb state expanded into the region during the twelfth century. Many toponyms in Kosovo appear to be Bulgarian. The name Kosovo appears in Bulgaria as Kosovo, Plovdiv Province. Arnavudluk (Albania) Kosovo was part of the Ottoman state for 457 years. Ottoman traveller Evliya Çelebi, who went to the area in 1660 referred to central Kosovo as Arnavud (آرناوود) and noted that in Vučitrn its inhabitants were speakers of Albanian or Turkish and few spoke "Boşnakca". The highlands around the Tetovo, Peja and Prizren areas Çelebi considered as being the "mountains of Arnavudluk". Çelebi referred to the "mountains of Peja" as being in Arnavudluk and considered the Ibar river that converged in Mitrovica as forming Kosovo's border with Bosnia. He viewed the "Kılab" or Lab river as having its source