Calais Staple to Westminster. But de la Pole had severely misread his audience. Attack on the royal prerogative The first—and for the King, most important—item of business on the parliamentary agenda was his request for a subsidy, or tax of movable goods, of four fifteenths and two-tenths, which was calculated to bring in the large sum of around £155,000. Saul has argued that "never before had such a sum been demanded, and it was this that precipitated Suffolk's fall. There was an immediate—and concerted—assault by the Commons and the Lords, who were "with one mind...complaining grievously". The Commons, to some degree representing public opinion, "demanded a scapegoat", says May McKisack. The Lords, encouraged by their most powerful members such as Thomas Beauchamp, Earl of Warwick and Richard Fitzalan, Earl of Arundel, the Archbishop of Canterbury and the Bishops of Winchester and Exeter, would have, it has been said, "presented a formidable opposition to a boy of nineteen", as the King was. The precise political manoeuvrings of the various parties are now obscured, but no royal business was transacted. At some point the discussions moved from the question of tax to that of the King's chancellor. However it came about, it certainly resulted in the King making a spirited defence of his right to choose his own ministers and of the royal prerogative. Conversely, the Commons demanded that the King appoint his councillors in parliament, effectively placing them under parliamentary oversight. Attack on Michael de la Pole It is possible that the original plan was to impeach Robert de Vere, who was felt to have at least as much influence with the King as Suffolk, if not more. However, that the attack was eventually launched on the chancellor is probably down to the simple fact that he was seen as more of a parvenu and thus, of the two, the easier target. Whatever the original tactics, the plan that was finally acted upon were to impeach de la Pole, and thus to attack the King indirectly; but the articles of impeachment were sloppily prepared—although the charges themselves were neither inconsequential nor insignificant, argues Roskell. As a result of poor preparation, the most general charges were unprovable. Others (for example, the conduct of the war with France) were shown to be the joint responsibility of the royal council, and so not solely Suffolk's fault; N. B. Lewis has questioned the validity of