inhabit the territory was the Agathyrsi, of the Scythic cultures. From the 4th century BC, Celtic La Tène culture came to domination. The indigenous Dacian tribes engaged in politics from the 1st century BC and united under King Burebista, forming their kingdom Dacia. The Roman Empire made heavy efforts to seize the territory from King Decebalus, resulting in the formation of Roman Dacia in 106, after Trajan's costly and bloody wars. During Roman rule, the territory, depleted of its indigenous population, was repopulated with Latin colonists and its rich resource stock was systematically exploited. However, due to the growing threat of East Germanic and Carpic invasions, Emperor Aurelian withdrew his legions and evacuated the citizens south of the Lower Danube in 275, after which the province was occupied by the Goths. In 376, a powerful nomadic people, the Huns, defeated and shattered the Goths, and settled in the area. After the death of Hun King Attila, their empire disintegrated and the Gepids conquered the region in 455, under King Ardaric. For two centuries, the Gepids controlled Transylvania. They waged war successfully against the Eastern Roman Empire, and less successfully against the Ostrogoths in Pannonia. They were defeated by the Lombards and Avars in 567. In the following years, the Avars took full control over Transylvania, heavily settling the area with Slavic tribes who accepted their suzerainty. The expansion of the Frankish Empire, however, imposed a growing threat on them and their khaganate was crushed in the Avar Wars. The Avars and Slavs, although substantially depleted in number, continued to inhabit the Carpathian Basin. The First Bulgarian Empire annexed Southern Transylvania. Smaller Slavic polities were also present, nevertheless they could hardly keep their independence. In the late 9th century, Transylvania was reached and conquered by the Hungarian conquerors. There is an ongoing scholarly debate over the demographics in Transylvania in this time. According to the theory of Daco-Roman Continuity, Romanians continuously lived on the territory for the past 2500 years. Opponents of this hypothesis point to the lack of written, archaeological and linguistic evidence to support this. Hungarian medieval chronicles claimed that the Székely people descended from the Huns, who remained in Transylvania, and later, in combination with the returning Hungarians, conquered the Carpathian Basin. According to the Gesta Hungarorum, the Vlach (Blacorum, Blacus) leader Gelou ruled part of Transylvania before the Hungarians arrived. Historians debate whether he was a historical