Henry VIII had a tough pickle, his Wife Catherine of Aragon, the Spanish queen, had a daughter, Mary, but England's Court will not have a woman as a monarch, much like the rest of Europe at the time, so Henry needed a Son badly for the crown sucession.
Catherine was old by then, I think it was 1520 or thereabouts, so she couldn't give him another child, so he needed a divorce to get a Son with someone else.
So Henry went to the Pope to get a nullification of their marriage, but low and behold, Rome is in the italian peninsula, and the crowned monarch recognized by Rome as well as Spain and Netherlands and the Central Europe, the Holy Roman Emperor was Charles V, Catherine's nephew, so the Pope couldn't say yes to Henry or he'll had to explain to Charles about his auntie, and Catherine refused the nullification on grounds that she wasn't unfaithful to Henry.