Christianity, Rulers and Raetia
In the beginning of the 5th century and during the 6th century, Christianity had taken root in Switzerland. The oldest church foundations of St. Maurice date from the 4th century, the monastery was founded around 515. In Romainmôtier, Geneva, Nyon, Yverdon, Avenches, Windisch, Augst, Basel, Martigny existed Christian congregations, churches or dioceses at that time. Moutier-Grandval and St. Ursanne were founded around 630. In the countryside, however, most of the congregations were not established until the 6th and 7th centuries. With their rise, the dioceses gradually expanded into the countryside.
Christianity was already firmly rooted in Raetia in the 5th century, and the bishops of Chur are known since 451. Around 600, a diocese was founded in Constance in the Duchy of the Alamanni. Raetia remained independent for a relatively long time, but the Carolingians became increasingly dominant. The Victoriden dynasty, which had ruled over Raetia since about 550, died out around 775 and Charlemagne appointed Frankish counts as rulers in Raetia.The Carolingians founded the monasteries Reichenau, Pfäfers, Disentis and appointed Frankish bishops in Constance and St. Gallen in the eight century. The Frankish rule was thus anchored to control the passes and roads to Lombardy. The Carolingian/Frankish rulers and their later successors in this area (from 962 the German kings and centuries later the Habsburg emperors) kept their influence for centuries to come, formally until the transfer of Tarasp (1803) and Rähzüns (1819) to the canton of Grisons. (Source: W. Drack, Die Schweiz im Frühmittelalter, Basel, 1959).