In the first half of the first century AD, the province of Raetia was created, covering the Alpine region between the Danube and the Inn River, modern Switzerland south of the Bodensee and the northern Tyrol, which had been brought under Roman control in 15 BC. Around 180 AD, Raetia was an Imperial province of the second class, governed by a senator of praetorian rank. In 297 AD, as part of Diocletian's reforms of the provinces, Raetia was split along the Bodensee and the northern East Alps, creating two new provinces: Raetia Prima or Curiensis in the east and Raetia Secunda or Vindelica in the west. Both provinces belonged to the Diocese of Italy and were under the control of a single military commander, the Dux Raetiae primae et secundae [de]. The civil administration of each province was entrusted to a praeses, a governor of lower rank. The residences of these two officials, Curia Raetorum (modern Chur) and Augusta Vindelicorum [de] (Augsburg), are the source of the later German language terms: Churrätien and Vindelicien.
Even after the Fall of the Western Roman Empire in 476 AD, the political connection of Rhaetia Prima with Italy survived to some extent. Initially, the province came under the control of Odoacer's kingdom of Italy.[4] After his death in 493, the Ostrogothic kingdom inherited control over the province.[5] The Ostrogothic king Theoderic the Great again placed Raetia Prima under the control of a Dux to ensure the security of Italy. Civil administration remained the responsibility of the Praeses. The main seat of administration was Chur, which is first attested as the seat of a bishopric in 452 AD. In 537 AD, the Ostrogothic king Witiges was forced to cede the portion of Raetia prima south of the Bodensee to the Frankish king Theudebert I, in exchange for support against the Byzantine Empire in the Gothic War.[6] When the Ostrogoths lost that war, Theudebert was able to bring the rest of Raetia Prima including the militarily and economically important Bündner pass under his control. How this occurred is not recorded, but it marked the end of the regions political connection to Italy.[7]
^Ursula Koch, "Besiegt, beraubt, vertrieben – Die Folgen der Niederlagen von 496/ 497 und 506" in Archäologisches Landesmuseum Baden-Württemberg (ed.): Die Alamannen, Verlagsbüro Wais & Partner, Stuttgart 1997, p. 196, ISBN 3-8062-1302-X
^Hasler, Heiligmann, Höneisen, Leuzinger, Swozilek (Hrsg.): »Im Schutze mächtiger Mauern – Spätrömische Kastelle im Bodenseeraum«, Verlag Huber & Co. AG, Frauenfeld 2005, p. 56, ISBN 3-9522941-1-X
^Amt für Archäologie des Kantons Thurgau: »Römer, Alemannen, Christen – Frühmittelalter am Bodensee«, Frauenfeld 2013, pp. 15 & 28, ISBN 978-3-9522941-6-1
^Otto P. Clavadetscher: »Churrätien im Übergang von der Spätantike zum Mittelalter nach den Schriftquellen«, in: Joachim Werner/ Eugen Ewig (Hrsg.):»Von der Spätantike zum frühen Mittelalter«, Sigmaringen 1979. pp. 165–168.