The origins of the Presbyterian Church is the Protestant Reformation of the 16th century. The writings of French theologian and lawyer John Calvin (1509–64) solidified much of the Reformed thinking that came before him in the form of the sermons and writings of Huldrych Zwingli. John Knox, a former Roman Catholic priest from Scotland who studied with Calvin in Geneva, Switzerland, took Calvin's teachings back to Scotland and led the Scottish Reformation of 1560. As a result, the Church of Scotland embraced Reformed theology and presbyterian polity. The Ulster Scots brought their Presbyterian faith with them to Ireland, where they laid the foundation of what would become the Presbyterian Church of Ireland.