The plague swept through Noyon leaving countless villagers dead. Fearing for John’s life, Gerhard appealed to the Bishop to allow John to complete his education in Paris while still receiving his allowance as Chaplain. The request was granted and John Calvin was sent to La Marche, one of the colleges of the University of Paris. Under the tutelage of Mathurin Cordier, Calvin’s intellectual abilities blossomed. Cordier’s mentorship profoundly impacted Calvin’s skills as a communicator and scholar. These skills would later make him a master of communicating the truth in the French language.

Once Calvin finished his training at La Marche he went to Montaigu College where he was further educated in church dogma. The scholars at the college predicted that Calvin would one day become a Cardinal, perhaps one of the most influential members of the College of Cardinals. He was on a path to becoming one of the brightest theologians in the Roman Catholic church. 

However, the presence of his cousin Pierre Olivetan provided Calvin with a much-needed catalyst to recalibrate his thinking. Olivetan was a disciple of the great protestant theologian Jacques Le Fevre, who was the first to teach the protestant principles of righteousness by faith in France. 

Olivetan began to spar with Calvin challenging his concepts of salvation, grace, and the church's role in the administration of both. “There are but two religions in the world” Olivetan is reported to have said to Calvin, “the one class of religions are those which men have invented, in all of which man saves himself by ceremonies and good works. The other is that religion which is revealed in the bible, and which teaches man to look for salvation solely from the free grace of God” 

Calvin was unwilling to accept Olivetan’s thesis, rejecting it with a vehement defense of papal dogma. However, Calvin began to struggle with his faith in private. Olivetan’s words cut him more deeply than he was willing to admit, causing him to question God’s acceptance of his works of merit. 

The sudden, chilling realisation that his good works might be inadequate to secure his salvation caused Calvin to tremble. He renewed his pursuit of salvation through the ordained channels of the church yet peace of mind eluded him. 

While grappling with these issues he witnessed the martyrdom of a young protestant at the Place de la Greve. The man, who was burnt at the stake for heresy faced death with peaceful assurance forcing Calvin to wonder how he could yield his life with such assurance while under the anathema of the church. 

Taking Olivetan’s advice Calvin began to study the Bible, there, like so many reformers before and after him he discovered salvation through Christ alone. This discovery irrevocably transformed his life. 

After completing his doctorate in law Calvin devoted himself fully to preaching salvation by faith. He began in the provincial town of Bourges, where he went from house to house, unobtrusively offering Bible studies to families around their fireplaces. 

Bourges, located in the province of Berry, was uniquely positioned to nurture Protestantism because it was under the governance of the king’s sister Margaret who was Queen of Navarre and Duchess of Berry. Margaret like Olivetan was a disciple of LeFevre and warmly welcomed Calvin’s missionary efforts. 

While he was laboring at Bourges Calvin received news of his father’s death which prompted him to return immediately to Noyon. After his departure, the protestant physician Michel Simon continued his work. After attending his father’s funeral Calvil travelled to Paris where he continued his missionary endeavors from house to house.