Slavs are the largest Indo-European ethno-linguistic group in Europe. They inhabit Central Europe, Eastern Europe, Southeast Europe, North Asia and Central Asia. Slavs speak Indo-European Slavic languages and share, to varying degrees, certain cultural traits and historical backgrounds. From the early 6th century they spread to inhabit most of Central and Eastern Europe and Southeast Europe, whilst Slavic mercenaries fighting for the Byzantines and Arabs settled Asia Minor and even as far as Syria. The East Slavs colonised Siberia and Central Asia. Presently over half of Europe's territory is inhabited by Slavic-speaking communities, but every Slavic ethnicity has emigrated to other continents.