 Calvin 's theology was not without controversy . Pierre Caroli , a Protestant minister in Lausanne accused Calvin as well as Viret and Farel of Arianism in 1536 . Calvin defended his beliefs on the Trinity in Confessio de Trinitate propter calumnias P. Caroli . In 1551 Jérôme @-@ Hermès Bolsec , a physician in Geneva , attacked Calvin 's doctrine of predestination and accused him of making God the author of sin . Bolsec was banished from the city , and after Calvin 's death , he wrote a biography which severely maligned Calvin 's character . In the following year , Joachim Westphal , a Gnesio @-@ Lutheran pastor in Hamburg , condemned Calvin and Zwingli as heretics in denying the eucharistic doctrine of the union of Christ 's body with the elements . Calvin 's Defensio sanae et orthodoxae doctrinae de sacramentis ( A Defence of the Sober and Orthodox Doctrine of the Sacrament ) was his response in 1555 . In 1556 Justus Velsius , a Dutch dissident , held a public disputation with Calvin during his visit to Frankfurt , in which Velsius defended free will against Calvin 's doctrine of predestination . Following the execution of Servetus , a close associate of Calvin , Sebastian Castellio , broke with him on the issue of the treatment of heretics . In Castellio 's Treatise on Heretics ( 1554 ) , he argued for a focus on Christ 's moral teachings in place of the vanity of theology , and he afterward developed a theory of tolerance based on biblical principles . 
