In 1637 King Charles I attempted to introduce an episcopal "Book of Common Prayer" which was seen as an attempt to anglicize Scotland and the Church. The Scots were outraged, particularly since there had been no prior discussion with the General Assembly, the governing body of the Church of Scotland. In St Giles Cathedral, Jenny Geddes famously hurled her stool at the pulpit screeching "Daur ye say mass in my lug" (Dare you say mass in my ear).

The following year, in February 1638, a new National Covenant was drawn up and thousands crowded into Greyfriar's Kirkyard in Edinburgh to sign it. This document drew on an earlier "King's Confession" from 1581 in which a covenant had been drawn up in which both the king and the people swore to maintain the Presbyterian system of church government. While the new document swore loyalty to the monarch, it nevertheless firmly restated the direct relationship between the people and God, with no interference from the king and "all kinds of Papistry." Within months, over 300,000 people had "covenanted" in what a writer of the day described it as "the glorious marriage day of the Kingdom [of Scotland] with God." The adherents were prepared to fight for their religious freedom - and soon were called upon to do so.