Celts in Transylvania arrived in northwestern Transylvania in around 400–350 BC as part of their great migration eastwards. When Celtic warriors first penetrated these territories, the group seem to have merged with the domestic population of early Dacians and assimilated many Hallstatt cultural traditions. The second half of the 4th century BC saw the Middle La Tène Celtic culture emerge in north-western and central Dacia, a development reflected especially in burials of the period. Celtic artifacts dating to this time have been discovered at Turdaş, Haţeg and Mediaş in modern-day Romania. By 1976, the number of Celtic sites found in Transylvania had reached
Celts in Transylvania found in Mediaș, Moreşti, (Mureş County) and Ciumeşti. Expansion of Celtic groups in the area may be related to their invasion of the Balkans around 335 BC, when a massive colonization of the Tisa plain and the Transylvanian Plateau occurred following the death of Lysimachus. However, the eastward movement of the Celts into Transylvania used a different route from the one taken by the hordes that attacked the Balkans. Celts did not occupy all intra-Carpathian areas of Transylvania, stopping short of the Maramureş Depression for instance, where excavations have uncovered Dacian fortifications from the 4th and 3rd centuries BC. As