"Oxford Martyrs" usually refers to three English Protestants, Nicholas Ridley, Hugh Latimer, and Thomas Cranmer, who were burned at the stake in Oxford in 1555 and 1556. The traditional place of the martyrdom (its exact site is unclear) is marked with a cross in Broad St outside Balliol College. A Victorian era monument to the three stands in St Giles.
Hugh Latimer was famous as a preacher. He was Bishop of Worcester in the time of King Henry, but resigned in protest against the King's refusal to allow the Protestant reforms that Latimer desired. Latimer's sermons speak little of doctrine; he preferred to urge men to upright living and devoutness in prayer. But when Mary came to the throne, he was arrested, tried for heresy, and burned together with Nicholas Ridley on 16 October 1555. His last words at the stake are well known: "Be of good cheer, Master Ridley, and play the man, for we shall this day light such a candle in England as I trust by God's grace shall never be put out."
Nicholas Ridley became an adherent of the Protestant cause while a student at Cambridge. He was a friend of Archbishop Cranmer and became private chaplain first to Cranmer and then to King Henry. Under the reign of Edward, he became bishop of Rochester, and was part of the committee that drew up the first English Book of Common Prayer. When Mary came to the throne, he was arrested, tried, and burned with Latimer at Oxford.
Thomas Cranmer was Archbishop of Canterbury under Henry, and defended the position that Henry's marriage to Katharine of Aragon (Spain) was null and void. When Edward came to the throne, Cranmer was foremost in translating the worship of the Church into English (his friends and enemies agree that he was an extraordinarily gifted translator) and securing the use of the new forms of worship. When Mary came to the throne, Cranmer was in a quandary. He had believed, with a fervor that many people today will find hard to understand, that it is the duty of every Christian to obey the monarch, and that "the powers that be are ordained of God" (Romans 13). As long as the monarch was ordering things that Cranmer thought good, it was easy for Cranmer to believe that the king was sent by God's providence to guide the people in the path of true religion, and that disobedience to the king was disobedience to God.
Now Mary was Queen, and commanding him to return to the Roman obedience. Cranmer five times wrote a letter of submission to the Pope and to Roman Catholic doctrines, and four times he tore it up. In the end, he submitted. However, Mary was unwilling to believe that the submission was sincere, and he was ordered to be burned at Oxford on 21 March 1556. At the very end, he repudiated his final letter of submission, and announced that he died a Protestant. He said, "I have sinned, in that I signed with my hand what I did not believe with my heart. When the flames are lit, this hand shall be the first to burn." And when the fire was lit around his feet, he leaned forward and held his right hand in the fire first.
Other martyrs of the Reformation era, both Protestant and Catholic, are now commemorated in the University Church of St Mary the Virgin on the High Street.