The riot against the Scottish Prayer Book of 1637 at St Giles in Edinburgh on Sunday, 23 July 1637, was the starting point of the British troubles in the mid-seventeenth century. The National Covenant, the two Bishops' Wars, the Long Parliament, and the English Civil War were inevitable chain reactions of the riot against the Prayer Book. It had been used as a piece of evidence for the Popish Plot by the Puritans on both sides of the border during the English Civil War. The Scottish Covenanters found the book ‘popish’ and accused William Laud of being a main composer of it. The archbishop was tried and executed amid the Scottish rage against the Prayer Book in January 1645.

But was it? Was it entirely popish? Could it be called an anglicization of Scottish worship? Was Laud alone responsible for that? What were the roles played by the king and the Scottish bishops? The Scottish Prayer Book of 1637 is the best key to the understanding of the nature of Charles's ecclesiastical policies of the 1630s in their British context. This is not simply because the composition and the imposition of this book occupied the whole of the 1630s, but also because from the first step to the last in this policy, its relation to the English liturgy dominated the British ecclesiastical policy of the 1630s.