Portrait of Knox from the original in the possession of Lord Torpichen at Calder House.

John Knox (c. 1510 – 24 November 1572) was a Scottish clergyman and a leader of the Protestant Reformation and he is considered the founder of the Presbyterian denomination. He was educated at the University of St Andrews and worked as a notary-priest. Influenced by early church reformers such as George Wishart, he joined the movement to reform the Scottish church. He was caught up in the ecclesiastical and political events that involved the murder of Cardinal Beaton in 1546 and the intervention of the regent of Scotland. He was taken prisoner by French forces the following year and exiled to England on his release in 1549.

When Mary Tudor ascended the throne and reestablished Roman Catholicism, Knox was forced to resign his position and leave the country. Knox first moved to Geneva and then to Frankfurt. On his return to Scotland, he led the Protestant Reformation in Scotland, in partnership with the Scottish Protestant nobility. Knox helped write the new confession of faith and the ecclesiastical order for the newly created reformed church, the Kirk. He continued to serve as the religious leader of the Protestants throughout Mary's reign. In several interviews with the queen, Knox admonished her for supporting Roman practices. Eventually, when she was imprisoned and James VI enthroned in her stead, he openly attacked her in sermons. He continued to preach until his final days.