Henry VIII fundamentally changed the nature of religion in England by breaking free of the Catholic Church. This established the groundwork for England to become a Protestant country.
Despite the radical changes he initiated, Henry was generally quite conservative when it came to religious matters, and it's important to remember that a number of true believers in the Protestant cause were put to death during his long reign.
The official position of the court changed rapidly during these turbulent decades, largely in response to political developments in Europe. When Henry needed to make alliances with Catholic powers, persecution of Lutherans and Calvinists was stepped up. When he needed the support of Protestant powers, it was time to crack down on those who adhered to the old faith.
Henry conceived of the Church of England in political rather than confessional terms, as primarily an instrument of his kingly power. In breaking free from Rome, he was affirming what he believed to be his God-given right as sovereign to determine the religious life of his realm.
Once he'd established himself as Supreme Head of the Church of England, loyalty to the new church was equated with loyalty to the king. Those who did not, or could not, subscribe to the new order were to be regarded as traitors who owed their allegiance to a foreign pope—or in the case of Calvinists, to a foreign ideology—and not to the king of England.
Although die-hard Protestants trod warily in case they incurred the wrath of the king, they took the opportunity given to them by the break with Rome to lay the groundwork for an authentic Reformed Church in England, one that would replicate the state church of Calvinist Geneva.
But they had to be careful. So long as the erratic Henry was alive, there was always the danger that his religious policy might change at the drop of a hat. As that policy was largely dictated by political necessity, the balance of power within the state between conservatives and reformers was always subject to change, with fatal consequences for the losers.
To some extent, Henry encouraged such tensions between the rival factions because they diverted his nobles' attentions away from potentially plotting against him. Throughout his entire reign, Henry was highly insecure about the stability of his throne. He saw the establishment of the Church of England, free from the Pope's control and with himself as its Supreme Head, as a way of consolidating his power and making himself the closest thing that England has ever had to an absolute ruler.