Shortly after the death of Beaton, John Knox came to Edinburgh as a newly ordained priest, having been accused of "hatching the plot" against the cardinal even though he did not
personally take a hand in executing it. Soon Knox had a growing group of followers. He accused the Catholic clergy of Scotland of being "gluttons, wantons and licentious revelers,
but who yet regularly and meekly partook of the sacrament." Knox traveled to Geneva three times to study under Calvin who had a high regard for the young Scotsman. Knox
returned to Scotland, was married at age 38, and was widowed a few years afterward.
"Mary, like her mother was Catholic in faith and in sentiment, and bore deep resentment towards her father and Protestants for the humiliation of her mother and herself during the
divorce days. When she tried to reintroduce Catholicism to the realm she met with resistance, and soon a reign of terror ensued. Knox, who was outspoken in his opposition to
Mary's appointment as queen, was persuaded to withdraw from England, and sailed for Dieppe (a port city in northern France), arriving in January 1554. The time afforded in his
exile gave the refugee an opportunity of completing and publishing several treatises, a letter to his former congregations entitled: A Godly Letter of Warning or Admonition to the

Models for Reformation: John Knox (1505-1572)
John Knox, Scottish Reformer and founder of Presbyterianism in Scotland
Faithful in London, Newcastle, and Berwick, general letters of encouragement to all the protestants in England entitled: Two Comfortable Epistles to his afflicted Brethren in
England, and a letter to the Protestant ministers in England entitled: A Faithful Admonition to the Professors of God's Truth in England, all written in 1554. He lived for a season in
Geneva, Switzerland in the congregation of John Calvin, and was most impressed. He accepted, in accordance with Calvin's council, an invitation to pastor an English
congregation-in-exile at Frankfort. Soon after his arrival controversies arose in the congregation in regard to the use of the surplice (long white linen vestment worn by priests and
Anglican ministers), the use or omission of the litany, and the kneeling at the receiving of communion (a practice described in the English Book of Prayer, but long opposed by
Knox when he was in England). Knox showed amazing restraint and an uncharacteristic willingness to compromise, to preserve unity. An adversary in the congregation, desiring a
strict adherence to the English Book of Prayer and seeking his position as pastor, forced him to resign by informing the magistrates of Frankfort (who were Protestant, but under
the protection of the emperor) that Knox had used treasonable language in speaking of the emperor (Charles ?), the queen of England, and her husband Philip II. On March 26,
1555, John Knox resigned the pastorate and returned to Geneva, where he was asked to pastor a refugee English congregation, a considerable number of whom were supporters
from the Frankfort congregation. Many historians cite this as the birth of English puritanism."
John Knox, 1505-1572 , biography
John Knox, the Watchman of Scotland (1505-1572)