After three years of exile, French theologian John Calvin returned to Geneva to reform the church under a system of Christian theology later known as Calvinism.

John Calvin was a French theologian, pastor and reformer in Geneva during the Protestant Reformation. He was a principal figure in the development of the system of Christian theology later called Calvinism, including its doctrines of predestination and of God's absolute sovereignty in the salvation of the human soul from death and eternal damnation. Calvinist doctrines were influenced by and elaborated upon Augustinian and other Christian traditions. Various Reformed Church movements, including Continental Reformed, Congregationalism, Presbyterianism, Waldensians, Baptist Reformed, Calvinist Methodism, and Reformed Anglican Churches, which look to Calvin as the chief expositor of their beliefs, have spread throughout the world.

Geneva is the second-most populous city in Switzerland and the most populous in French-speaking Romandy. Situated in the southwest of the country, where the Rhône exits Lake Geneva, it is the capital of the Republic and Canton of Geneva. and a centre for international diplomacy. Geneva is a global city, an international financial centre, and a worldwide centre for diplomacy, which has led to it being called the "Peace Capital".

The Reformation, also known as the Protestant Reformation or the European Reformation, was a time of major theological movement in Western Christianity in 16th-century Europe that posed a religious and political challenge to the papacy and the authority of the Catholic Church. Towards the end of the Renaissance, the Reformation marked the beginning of Protestantism. It is considered one of the events that signified the end of the Middle Ages and the beginning of the early modern period in Europe.

Christian theology is the theology – the systematic study of the divine and religion – of Christian belief and practice. It concentrates primarily upon the texts of the Old Testament and of the New Testament, as well as on Christian tradition. Christian theologians use biblical exegesis, rational analysis and argument. Theologians may undertake the study of Christian theology for a variety of reasons, such as in order to:

• help them better understand Christian tenets
• make comparisons between Christianity and other traditions
• defend Christianity against objections and criticism
• facilitate reforms in the Christian church
• assist in the propagation of Christianity
• draw on the resources of the Christian tradition to address some present situation or perceived need
• education in Christian philosophy, especially in Neoplatonic philosophy