Henry had been given the title 'defender of the faith' by the Pope and he had been a devout Catholic. However when he was blocked in his efforts to marry Anne Boleyn and therefore try to have a legitimate male heir, he turned on the Catholic Church and split from Rome in the Act of Supremacy of 1534.
This act was very significant as it established the monarch as Head of the English Church and ended the Pope's authority in England. As part of this process Henry attacked the monastries sending investigators in to them in order to find evidence of their misdeeds. This gave him the excuse to close them and seize their wealth for himself and his supporters. It was a massive act of cultural vandalism as the centuries old monasteries were left as ruins, as they stand today. With these changes Henry set in place a process that was never reverted, even though his daughter Mary tried for a short period to do so - the Reformation of the Church was fully cemented in the creation of the Church of England under the long reign of his daughter Elizabeth.