By 1540 Cromwell's influence was declining. However, the catalyst for his downfall, as with Wolsey, was his failure to manage the king's marital affairs satisfactorily. In 1537 Henry's third wife, Jane Seymour, had died, after giving birth to the long-awaited male heir, Prince Edward. In 1540 Cromwell had tried to reconcile Henry with the League of Schmalkalden, an organisation of German princes and free cities within the Holy Roman Empire who supported the reformer Martin Luther and his rejection of the Catholic Church, by arranging a marriage with a German Protestant princess, Anne of Cleves. This was an unhappy partnership on multiple levels: Anne proved unsuitable to Henry personally, and the match had become unwelcome politically. The marriage was quickly annulled, destroying what remained of Cromwell's credibility with the king.
This gave his enemies, led by the Duke of Norfolk, the chance to bring about his downfall. Norfolk was once again aided by having a niece, the Catholic Catherine Howard, at court and conveniently free to wed the king.
Cromwell was accused of treason and heresy at a Council meeting and was executed on 28 July 1540. Henry and Catherine married on the same day.
Two days later, the message that the Protestant Reformation cause was in tatters was reinforced by the burning for heresy of three Protestant theologians. Henry, however, demonstrated his even-handedness by ensuring the execution on the same day of three Catholic priests, who had been imprisoned for six years, for treason in denying the royal supremacy.