Polabian Slavs, also known as Elbe Slavs, is a collective term applied to a number of Lechitic (West Slavic) tribes who lived scattered along the Elbe river in what is today eastern Germany. The approximate territory stretched from the Baltic Sea in the north, the Saale and the Limes Saxoniae in the west, the Ore Mountains and the Western Sudetes in the south, and Poland in the east. The Polabian Slavs were largely conquered by Saxons and Danes since the 9th century and were subsequently included and gradually assimilated within the Holy Roman Empire. The tribes were gradually Germanized and assimilated in the following centuries; the Sorbs are the only descendants of the Polabian Slavs to have retained their identity and culture. The Polabian language is now extinct. However, the two Sorbian languages are spoken by approximately 22,000-30,000 inhabitants of the region and the languages are regarded by the government of Germany as official languages of the region. The Bavarian Geographer, an anonymous medieval document compiled in Regensburg in 830, contains a list of the tribes in Central Europe to the east of the Elbe. Among other tribes it lists the Uuilci (Veleti) with 95 civitates, the Nortabtrezi (Obotrites) with 53 civitates, the Milzane (Milceni) with 30 civitates, and the Hehfeldi (Hevelli) with 14 civitates. The Great Soviet Encyclopedia classifies the Polabian Slavs in three main tribes, the Obotrites, the Veleti, and the Lusatian Sorbs. The main tribes of the Obotritic confederation were the Obotrites proper (Wismar Bay to the Schweriner See); the Wagrians (eastern Holstein); the Warnabi (Warnower) (the upper Warnow and Mildenitz); and the Polabians proper (between the Trave and the Elbe). Other tribes associated with the confederation include the Linones (Linonen) near Lenzen, the Travnjane near the Trave, and the Drevani in the Hanoverian Wendland and the northern Altmark.