from an old textbook:

MARY TUDOR AS QUEEN: THE RECONCILIATION OF ENGLAND WITH ROME

MARY I, daughter of the unfortunate Queen Katherine, was received with enthusiasm as the rightful Queen and victor over the scheming and unpopular Northumberland. 

The new queen was honest and brave, as she proved by the way she faced all the dangers that beset her during her reign; she had the dignity and royal bearing of her father, and the pride of her Spanish mother; she meant to be a good ruler and had the interests of her people genuinely at heart. 

Mary's character

But Mary was one of the most unfortunate queens that ever reigned. Her childhood had been a most unhappy one. She could remember very vividly her mother's humiliation by Henry VIII, and he had treated her most unkindly too, for many years refusing to allow her even to appear at his court. 

It must also be remembered that Mary was not entirely English – though she had her share of the fierce Tudor temper – and her Spanish blood gave her character a melancholy strain. In spite of her good intentions her reign proved to be a complete tragedy. It was extremely difficult for a woman to rule in those days; around her at court were many "time-servers" out merely for their own gain, and Mary felt there were few she could trust. Always a staunch Catholic, she made it clear that she would now as Queen restore the old religion; and this indeed was her main object for she deemed it necessary for the souls of her subjects. 

Her aim to reintroduce Catholicism

So Mary went publicly to Mass, saying she trusted that her people would follow suit. She released several persons who had been imprisoned in the Tower during the previous reign on account of their religious beliefs, and restored them to their old positions. Among these was Bishop Gardiner of Winchester, whom she made her Chancellor. 

It was impossible for the queen to induce all who had been enriched with Church property to give it back, and Parliament would not allow her even to try. But Mary did what she could in this way by restoring Church lands that had become crown property, and once more there were monks installed in Westminster Abbey. 

The problem of land

Mass was said again in the churches, and the English Prayer Book discarded. Cardinal Pole, an Englishman of noble descent who had been in exile for many years, came to give the Pope's pardon and receive England back into the Church of Rome again. 

Roman Catholicism restored

But the flood of new doctrines allowed to spread unchecked during the reign of Edward VI had taken greater hold than Mary realised, and these now became more and more identified with disloyalty to her as Queen. She grew alarmed, and in her fear began to adopt the harshest methods in order to try and force her people to return to the old faith. 

Opposition

She got her Parliament to revive the Statutes for the burning of heretics, which had in the fourteenth and fifteenth centuries been enforced against the Lollards. Those who persisted in holding to the new doctrines were condemned to death by burning as heretics; and so strict was the queen in enforcing this penalty that about 300 Protestants suffered this death during her short rule of five years rather than "retract," i.e. take back their opinions. 

Burning heretics

The most notable among the people who died for their Protestant beliefs during Mary's rule were Bishops Latimer and Ridley, and Thomas Cranmer, Archbishop of Canterbury. 

Latimer and Ridley suffered together in 1555. Latimer was an old and feeble man at this time, but lie faced death bravely. "Be of good cheer," he said to Ridley at the stake, "we shall this day light such a candle, by God's grace, in England, as I trust shall never be put out." 

Latimer and Ridley

Archbishop Cranmer had been a prominent person in the spread of Protestant doctrines, for it was he who had compiled the English Prayer Book. He was tried for heresy in 1556. Several times he signed a paper of "recantation." The law of the land was for the present enforcing the old faith and submission to the Pope, and perhaps the timid Archbishop felt he ought to obey after all. However, it soon became clear that his life would not in any case be spared, for he had supported Lady Jane Grey.  At the last his courage returned, and he took back his submission and behaved with great bravery at the stake. He held his right hand, which had signed the recantations, steadily in the flames so that it should be consumed first, and died declaring himself a Protestant. 

Cranmer

Mary's treatment of Protestants was for her own aim a dreadful mistake. Far from making England Catholic again, it gave rise to such strong feeling against Rome that it did the Catholic cause much more harm than good. And when she made her second big mistake by marrying the Spanish prince, the Catholic Church became identified in English minds with Spanish authority.  A and so detestable to many. The wisest of her advisers, and even Philip of Spain himself, tried to persuade her that she was going too far, but the queen was obstinate and determined, and never allowed the persecution to relax. 

Mary's mistake

The practice of burning for heresy did not cease with Mary's death. Elizabeth I and James I had several persons burnt for maintaining doctrines which the English Church looked upon as heretical. The last burnings for heresy in England took place in the year 1612.  

Margaret Elliot, Britain under the Tudors and Stuarts (1961)