Parliament was summoned in September 1399 because King Richard II had been deposed by his cousin, Henry of Bolingbroke, the eldest son of John of Gaunt. Parliament unanimously accepted the 33 articles of deposition on 1 October and a fortnight later Henry IV was crowned king. Effectively, Henry used parliament to validate his actions and to give authority to his reign. Of course one of the difficulties was that Richard had already by deposed so there was technically no monarch to open the so called Convention Parliament which was then recalled after the 13th October in the name of Henry IV.

Parliament increasingly recognised that it held the right to withhold new taxes. It used this power to withhold funds until it got what it wanted from the monarch and in 1414, the Commons successfully ensured that it was them rather than the Lords who held the power in voting taxes for the king or not. By the time Henry V died in 1422 there could be no taxation and no new laws without parliamentary agreement, and more importantly it was the Commons who wielded the stronger power.

As the fifteenth century progressed Parliament was often used to pass acts of attainder against either the Yorkist or Lancastrian nobility depending which side was in the ascendent and by kings to justify why they should be on the throne. The monarchy was still powerful but because of the challenges it faced during the fifteenth century parliament was growing in importance and felt more able to challenge the king, even if he was still on the throne by Divine Right. King’s validated their rule through acts of Parliament and by using acts of attainder to punish men who fought against them.