was in Roman times shared between Venetia et Histria (region X of Roman Italia in the classification of Augustus) and the provinces Pannonia and Noricum. The Romans established posts at Emona (Ljubljana), Poetovio (Ptuj), and Celeia (Celje); and constructed trade and military roads that ran across Slovene territory from Italy to Pannonia. In the 5th and 6th centuries, the area was subject to invasions by the Huns and Germanic tribes during their incursions into Italy. A part of the inner state was protected with a defensive line of towers and walls called Claustra Alpium Iuliarum. A crucial battle between Theodosius I and Eugenius took place in the Vipava Valley in 394. Slavic settlement The Slavic tribes migrated to the Alpine area after the westward departure of the Lombards (the last Germanic tribe) in 568, and under pressure from Avars established a Slavic settlement in the Eastern Alps. From 623 to 624 or possibly 626 onwards, King Samo united the Alpine and Western Slavs against the Avars and Germanic peoples and established what is referred to as Samo's Kingdom. After its disintegration following Samo's death in 658 or 659, the ancestors of the Slovenes located in present-day Carinthia formed the independent duchy of Carantania, and Carniola, later duchy Carniola. Other parts of present-day Slovenia were again ruled by Avars before Charlemagne's victory over them in 803. Middle Ages The Carantanians, one of the ancestral groups of the modern Slovenes, particularly the Carinthian Slovenes, were the first Slavic people to accept Christianity. They were mostly Christianized by Irish missionaries, among them Modestus, known as the "Apostle of Carantanians". This process, together with the Christianization of the Bavarians, was later described in the memorandum known as the Conversio Bagoariorum et Carantanorum, which is thought to have overemphasized the role of the Church of Salzburg in the Christianization process over similar efforts of the Patriarchate of Aquileia. In the mid-8th century, Carantania became a vassal duchy under the rule of the Bavarians, who began spreading Christianity. Three decades later, the Carantanians were incorporated, together with the Bavarians, into the Carolingian Empire. During the same period Carniola, too, came under the Franks, and was Christianised from Aquileia. Following the anti-Frankish rebellion of Liudewit at the beginning of the 9th century, the Franks removed the Carantanian princes, replacing them with their own border dukes. Consequently, the Frankish feudal system reached the Slovene territory. After the victory