King and Parliament
In 1509 England's new king was the eighteen-year-old Henry VIII. He was the ruler of Wales as well, and his family, the Tudors, were partly Welsh. But he was not king of Scotland. (Scotland had its own king.)
The king was the real ruler, too. He was the head of the Government. He chose his ministers and advisers, and if he did not like their advice he could ignore it. If they displeased him he could sack them. Unlucky or careless ministers sometimes lost their heads.
The king could declare war and make peace as he liked. Most kings were soldiers, and led their men into battle. But to pay for wars, the king needed taxes. And to charge taxes, or make new laws, the king needed the help of Parliament.
There were (and still are) two houses of Parliament - the House of Lords and the House of Commons. All nobles (dukes, earls, and barons) and bishops sat in the House of Lords. The House of Commons contained some of the gentry, and some rich merchants from the towns.
Parliament did not sit all the time. There was a meeting when the king decided to have one. Usually, this was when he needed money, and wanted new taxes. Between 1509 and 1529, Parliament met only four times, each time for just a few weeks. (After 1529 it met much more often.)
Walter Robson: Crown, Parliament and People; Oxford University Press, 1992/2002, page 14 f.