John Calvin (Middle French: Jean Cauvin) (10 July 1509 – 27 May 1564) is an influential French theologian and pastor during the Protestant Reformation.

He is a principal figure in the development of the system of Christian theology later called Calvinism.

Originally trained as a humanist lawyer, he breaks from the Roman Catholic Church around 1530.

After religious tensions provoke a violent uprising against Protestants in France, Calvin flees to Basel, Switzerland, where in 1536 he publishes the first edition of his seminal work Institutes of the Christian Religion.

In this year, Calvin is invited by William Farel to help reform the church in Geneva.

The city council resists the implementation of Calvin and Farel's ideas, and both men are expelled.

At the invitation of Martin Bucer, Calvin proceeds to Strasbourg, where he becomes the minister of a church of French refugees.

He continues to support the reform movement in Geneva, and is eventually invited back to lead its church.

Following his return, he introduces new forms of church government and liturgy, despite the opposition of several powerful families in the city who try to curb his authority.

During this period, Michael Servetus, a Spaniard known for his heretical views, arrives in Geneva.

He is denounced by Calvin and executed by the city council.

Following an influx of supportive refugees and new elections to the city council, Calvin's opponents are forced out.

Calvin spends his final years promoting the Reformation both in Geneva and throughout Europe.

Calvin is a tireless polemic and apologetic writer who generates much controversy.

He also exchanges cordial and supportive letters with many reformers including Philipp Melanchthon and Heinrich Bullinger.

In addition to the Institutes, he writes commentaries on most books of the Bible as well as theological treatises and confessional documents, and he regularly gives sermons throughout the week in Geneva.

Calvin is influenced by the Augustinian tradition, which leads him to expound the doctrine of predestination and the absolute sovereignty of God in salvation of the human soul from death and eternal damnation.

Calvin's writing and preachings provide the seeds for the branch of theology that bears his name.

The Presbyterian and other Reformed churches, which look to Calvin as a chief expositor of their beliefs, have spread throughout the world.