After the Migration Period
The religious landscape in Switzerland changed with the Migration Period and the decline of the Western Roman Empire (around ad 480). Early Christianity, which had blossomed along the highroads and in the Roman settlements, now had to assert itself against the “pagan” Alemanni and Arian Burgundians. In addition, around the year 610, Irish missionaries introduced “evangelical” beliefs that forewent the Roman church organisation.
Until the close cooperation between “Rome” and the aspiring Carolingians there must have been real chaos as far as religion was concerned. The Pope and the Emperor (Charlemagne) then saw to it that there was standardisation, thus consolidating Roman Catholic style Christianity.
What began as the Roman Imperial Church with the Edict of Thessalonica (or Cunctos populos) in ad 380 continued its triumphal march in the fifth century as the Franconian Imperial Church. The Church and the secular rulers were united again, imperial monasteries like the one in Reichenau, had to serve Franconian imperial policy, in the bishoprics the bishops acted both as spiritual and secular rulers, and an office of the Church was basically linked to the right to worldly goods, in other words sinecures. The seeds that would lead to misuse, randomness and secularisation were thus sown in the official Church, and these would later provide the basis for the Reformation in the 16th century.