As a minor, Edward VI was the subject of power plays by those who wanted to be Protector (a phrase now normally replaced by the word Regent), firstly the Seymours (due to their relationship with Jane Seymour, Edward's mother) and afterwards the Dudleys.

Protector Dudley had a vested interest in Jane as he had married off his son Guildford to her and is considered to have persuaded Edward in his last illness to change the succession.

When Edward died, the new will was presented as a fait accompli and the intention was that Henry's daughters should be arrested but they had been warned and escaped and Mary was able to rally popular support that led to support for Jane crumbling and enabling her to gain the throne.

Mary originally was determined on clemency as she realised that Jane had been an unwilling tool in all of this, but Jane's father led a rebellion that showed she could be a focus of danger and disaffection. Also her intended Bridegroom, Phillip of Spain, was reluctant to come to England whilst this danger existed. Jane refused to renounce her Protestant faith and so Mary, who was determined to return England to the Catholic faith, did not exercise the clemency she had promised and Jane and Guildford went to the block.