 Following his return , Calvin introduced new forms of church government and liturgy , despite opposition from several powerful families in the city who tried to curb his authority . During this period , Michael Servetus , a Spaniard regarded by both Catholics and Protestants as having a heretical view of the Trinity , arrived in Geneva . He was denounced by Calvin and burned at the stake for heresy by the city council . Following an influx of supportive refugees and new elections to the city council , Calvin 's opponents were forced out . Calvin spent his final years promoting the Reformation both in Geneva and throughout Europe . 
