The Lords of the Congregation were a group of Protestant Scottish nobles who in the mid-16th century favoured reformation of the church along Protestant principles and a Scottish-English alliance. They had opposed the marriage of the young Queen Mary - daughter of James V and Mary of Guise - to the Dauphin of France (who became King Francis II of France from 1559 to 1560) and signed the 'First Band' or Covenant to work to make Scotland Protestant.
Following religious riots in Perth, the Lords gained support and provided military help to John Knox in opposing the troops of Mary of Guise. Near Cupar, in Fife, the Lords were strong enough to face-off a French and Scottish army jointly led by the Duke of Chatelherault, who as Regent had supported the French match, and D'Oysel the French king's lieutenant. By July 1559 the Lords of the Congregation had taken Edinburgh. As Edinburgh Castle was held against them, the Lords withdrew under the terms of the truce of the Articles of Leith.
In September, Chatelherault, now joined by his son the Earl of Arran, changed sides and became leader of the Congregation Lords. Mary of Guise, who had earlier offered a degree of religious tolerance, maintained that their motives were secular in part. Queen Mary and King Francis wrote to her in November 1559, declaring that the lords were acting maliciously under the name and cloak of religion. French re-inforcements pushed the Lords and their Protestant army back to Stirling and Fife.
By the Treaty of Berwick in February 1560, the Lords brought in an English army to resist the French troops. The armed conflict now centered on the Siege of Leith. After the death of the Queen Regent in June and the conclusion of hosilities at Leith by the Treaty of Edinburgh in July, the Scottish Reformation was effected - through the Scots Confession of Faith - in the Parliament of Scotland in August 1560.
After events reported in the document described here, the Congregation suffered a series of setbacks, with Mary of Guise retaking Edinburgh. However the arrival of English troops by sea in January 1560 sealed the course of reformation in Scotland. The Reformation Parliament which was convened in Edinburgh 10 July 1560 would appoint John Knox and others to draw up the Scots Confession of Faith.
Thomas Henderson referred to in the document was a burgess of Jedburgh at this time, and Sir John Forster (c.1515-1602) was an English administrator in the Scottish borders, deputy warden of the English middle march.