Although the phrase had been used for a number of years by Independents, it became politically significant in April 1648 during the three-day prayer meeting at Windsor Castle by the leadership of the New Model Army. The Army leadership felt deeply betrayed by the King because they thought that while they had been negotiating in good faith he had duplicitously gone behind their backs in making The Engagement with the Scots and encouraging a new civil war. At the end of the meeting the Grandees of the Army accepted that it was their duty "to call Charles Stuart, that man of blood, to an account for that blood he had shed, and mischief he had done".