After the Alpine regions were conquered during the campaigns of Emperor
Augustus in 15 BC, the lands between the
Inn and
Danube rivers were incorporated into the
Provincia Raetia et Vindelicia, an
Imperial province governed by a
Senator exercising the functions of a
Praetor. The province was divided into the mountainous part of
Raetia prima and northeastern
Raetia secunda in the
Alpine foothills during the reforms enacted by Emperor
Diocletian in 297. Both were assigned to the
Diocese of Italia under the
Praetorian prefecture of Italy and placed under the military authority of a
dux. The civil administration was entrusted to lower-ranking
praeses officials, who took their seats at
Curia Raetorum (Chur) and
Augusta Vindelicorum (
Augsburg). The northeastern border of
Raetia Curiensis with
Raetia Vindelica cannot be determined exactly. During the
Christianization in the 4th century, the
Bishopric of Chur arose in
Raetia Curiensis; a first bishop is mentioned in 451/52. Still under Italian rule during the tenure of King
Odoacer,
Raetia Curiensis nominally passed to
Ostrogothic Kingdom in 493, and King
Theoderic the Great again began to appoint
dux governors, who however had only military competences, while civil administration remained with a
praeses. Nevertheless, it appears that the Chur bishops remained
de facto independent rulers. In 537 King
Vitiges had to cede the northern lands up to
Lake Constance to the
Frankish king
Theudebert I in turn for his support in the
Gothic War against the
Byzantine Empire. Shortly afterwards, by 548, Theudebert expanded his rule over all the Churraetia lands, which finally lost the direct connection to Italy. Nevertheless, though there are only very limited historical sources for the following
Merovingian period, the commercial ties with the Italian
Kingdom of the Lombards south of the Alps remained vital. It also seems likely that the bishops of Chur still remained in charge as
de facto rulers of what was now a remote province on the outer margins of the Frankish kingdom, until in the 740s the
Carolingian campaigns against the likewise
de facto independent duchy of
Alemannia re-attached it to the realm. Several ecclesiastical and secular offices were held by members of the
Victorid dynasty. In the mid-8th century a surviving
Lex Romana Curiensis, a "Roman Law of Chur", was an abbreviated epitome of the
Breviary of Alaric. After the death of the last Victorid bishop
Tello of Chur in 765, King
Charlemagne took the occasion to issue a document of protection declaring Tello's successors his vassals. From the 770s onwards, Charlemagne appointed the bishops of Chur himself, increasing Frankish control over the territory. Upon the death of Bishop Remedius in 806 or 807, he legislated a division between episcopal and comital property (
divisio inter episcopatum et comitatum), ending the
de facto secular rule of the Chur bishops. He appointed Hunfried I
comes curiensis (or
Reciarum comes), ruling over a vast Imperial
demesne. The ecclesiastical (episcopal) and secular (comital) claims to power remained a source of contention. With Churraetia as a power base, the
Hunfriding heirs were able to gather enough power that Count
Burchard II was able to proclaim himself a
duke of Swabia in 917. At the same time, the former
Raetia province was absorbed into the re-established Swabian
stem duchy. For this reason, Churraetia remained nominally part of Swabia and by extension of the
Holy Roman Empire even though it had not historically been part of Alemannia. Chur suffered several invasions in the 10th century, by the
Magyars in 925/6, and by the
Saracens in 940 and 954. In parallel with the development of
feudalism in Western Europe, political power became fragmented over the 10th and 11th centuries, and Churraetia was divided into the three counties of
Oberrätien, Unterrätien and
Vinschgau. In the 12th century, these fell to the counts of
Buchhorn,
Bregenz and
Tyrol, respectively. In the later medieval period, the bishops of Chur regained a certain amount of secular influence, which was however more limited in extent, restricted to the Chur itself, the
Domleschg,
Engadin,
Bergell,
Chiavenna,
Bormio and
Vinschgau.
Raetia as a geographic designation remained in use at the end of the medieval period, when political power passed to the
Three Leagues (
Drei Bünde) federation. When the Free State of the Three Leagues eventually joined the
Helvetic Republic in 1798, the territory was incorporated as the
Canton of Raetia. Finally, with the Napoleonic
Act of Mediation of 1803, establishing the
Swiss Confederacy, the canton was named Grisons (
Graubünden). ==Germanic–Latin boundary==