John Calvin was born in Picardy on 10 July 1509 -- his dad was a bureaucrat in the Church and expected all his sons who made it past childhood to become priests (broadly understood) and John was sent off for a religious education. But as times changed, his dad thought there was more money to be made as a lawyer and John shifted to law school.
He developed the combined qualities of a theologian and a lawyer (insert your own joke here) and spent most of his adult life sermonizing [yelling] about how sinful everyone he didn't like was being, and organizing those complaints into a theology that became the guidebook for several Protestant denominations.
Most people think of Geneva as the Calvinist HQ, but he actually spent a lot of time holed up in Strasbourg because it was a 'free city' in the Holy Roman Empire and various authorities couldn't put their hands on him there no matter how much he annoyed them. (Which was a lot.)
He did become an authority himself in Geneva and used his power to weaponize the civil and church institutions there to punish his critics. Since many Protestant denominations sent their adherents to North America there is no shortage of apologists for Calvin in our churches here in the USA, for example:
https://www.desiringgod.org/articles/whitewashed-heroes
Still, even the relatively bland articles at Biography.com cannot avoid presenting some of his true character:
'While instituting many positive policies, Calvin's government also punished "impiety" and dissent against his particularly spare vision of Christianity with execution. In the first five years of his rule in Geneva, 58 people were executed and 76 exiled for their religious beliefs. Calvin allowed no art other than music, and even that could not involve instruments.'
One of his more infamous acts of chastisement involved a Spanish character now known as Michael Servetus. Instead of leaving it to Catholic authorities to decide how to punish Servetus, Calvin jumped the gun and had him burnt at the stake in 1553. His colleagues requested that he just have Servetus beheaded -- show some mercy, dude! -- but that wasn't enough for J.C.
https://en.wikipedia.org/wiki/Michael_Servetus
You may have heard of the acronym TULIP , even if only as part of a few jokes, but that describes Calvinism in five easy pieces. There is yet another apologia that explains the five leaves here:
https://reformedjournal.com/the-problem-with-tulip-or-more-than-tulips-in-this-field/
Calvin was buried, after his death in 1564, in an unmarked grave in Geneva - they say it was to keep him from being venerated as a saint. It makes me think of Rick Steves' line in his program on Spain about Franco's mausoleum -- some go to pay their respects and others to make sure he's still buried.
Star Trek fans should note that Calvin was called the Picard because that was his birthplace; Calvin and Hobbes fans should note that their creator went to Kenyon College and studied poli sci there before becoming a cartoonist.
Relevance for travel: Geneva, Strasbourg, Christendom, the Protestant rebellion, Puritanism. Recommended reading: all the links above.