John Calvin was a French theologian, pastor and reformer in Geneva during the Protestant Reformation.
Saint Ambrose was a renowned bishop of Milan and a key theologian, instrumental in the conversion of Saint Augustine and a major influence on the development of Western Christianity.
Saint Paul was an influential Christian missionary and theologian whose teachings significantly shaped the development of early Christianity.
Philip Jakob Spener was a prominent German theologian and Lutheran minister who significantly influenced the rise of Pietism in the late 17th century.