Captured by the Romans, 120 B.C., first bishop, Saint Isaac (c.400).
From 1154, under Emperor Conrad II, the bishops were princes of the Holy Roman Empire, but had to maintain a long struggle for their independence against the counts of Geneva and of Savoy.
Protestantism was established by law in 1535, the bishop was driven from his see, and the city became the "Protestant Rome" under Calvin's absolute rule.
Saint Francis de Sales, while bishop (1602-1621), restored to Catholicity a large part of the diocese, which was joined to Lausanne in 1819.
New Catholic Dictionary