Starting around 400 BC, Celtic groups, moving out of their La Tène cultural heartland in southern Germany/eastern Gaul, penetrated and settled south-eastern Europe as far as the Black Sea and into Anatolia. By c. 250 BC, much of the modern states of Austria, Slovakia, Hungary and Romania, and Bessarabia and Moesia, were under Celtic cultural influence and probably political domination in many regions. This migratory process brought Celtic material culture, especially advanced in metallurgy, to the Illyrian and Dacian tribes. Especially intensive Celtic settlement, as evidenced by concentrations of La Tène-type cemeteries, took place in Austria, Slovakia, the Hungarian Plain, Transylvania, Bessarabia and eastern Thrace. Central Transylvania appears to have become a Celtic enclave or unitary kingdom, according to Batty. It is likely that during the period of Celtic pre-eminence, the Dacian language was eclipsed by Celtic dialects in Transylvania. In Moesia, South of the Danube, there was also extensive Celticisation. An example is the Scordisci tribe of Moesia Superior, reported by the ancient historian Livy to be Celtic-speaking and whose culture displays Celtic features.