Romans did not abandon their fortresses along the northern banks of the Lower Danube for decades, and Dobruja (known as Scythia Minor) remained an integral part of the Roman Empire until the early 7th century. Middle Ages The Goths were expanding towards the Lower Danube from the 230s, forcing the native peoples to flee to the Roman Empire or to accept their suzerainty. The Goths' rule ended abruptly when the Huns invaded their territory in 376, causing new waves of migrations. The Huns forced the remnants of the local population into submission, but their empire collapsed in 454. The Gepids took possession of the former Dacia province. The nomadic Avars defeated the Gepids and established a powerful empire around 570. The Bulgars, who also came from the Eurasian steppes, occupied the Lower Danube region in 680. Place names that are of Slavic origin abound in Romania, indicating that a significant Slavic-speaking population lived in the territory. The first Slavic groups settled in Moldavia and Wallachia in the 6th century, in Transylvania around 600. After the Avar Khaganate collapsed in the 790s, Bulgaria became the dominant power of the region, occupying lands as far as the river Tisa. The Council of Preslav declared Old Church Slavonic the language of liturgy in the First Bulgarian Tsardom in 893. The Romanians also adopted Old Church Slavonic as their liturgical language. The Magyars (Hungarians) took control of the steppes north of the Lower Danube in the 830s, but the Bulgarians and the Pechenegs jointly forced them to abandon this region for the lowlands along the Middle Danube around 894. Centuries later, the Gesta Hungarorum wrote of the invading Magyars' wars against three dukes—Glad, Menumorut and the Vlach Gelou—for Banat, Crișana and Transylvania. The Gesta also listed many peoples—Slavs, Bulgarians, Vlachs, Khazars, and Székelys—inhabiting the same regions. The reliability of the Gesta is debated. Some scholars regard it as a basically accurate account, others describe it as a literary work filled with invented details. The Pechenegs seized the lowlands abandoned by the Hungarians to the east of the Carpathians. Byzantine missionaries proselytised in the lands east of the Tisa from the 940s and Byzantine troops occupied Dobruja in the 970s. The first king of Hungary, Stephen I, who supported Western European missionaries, defeated the local chieftains and established Roman Catholic bishoprics (office of a bishop) in Transylvania and Banat in the early 11th century. Significant