Who was the Catholic that was executed and later canonized as a saint during Henry VIII’s reformation of England?
The name of the man that you are looking for is Sir Thomas More. He was an important councilor to Henry VIII until he and Henry became estranged over matters of religion. He was executed in 1535 and was canonized (made a saint) by the Catholic Church 400 years later, in 1935.
Sir Thomas More was born in England in 1478. He considered becoming a priest and remained a very devout Catholic for his entire life. However, he did not join the Church and instead became a lawyer and went into politics. He had a long career in government. He was also a Humanist scholar and philosopher and is famous for his book Utopia, in which he considers what an ideal society would look like.
More became Henry VIII’s chancellor in 1529. This was a very high position in government and More performed very well in that capacity. He was a strong supporter of Henry. However, More was unable to support Henry’s rebellion against the Church as a whole. When Henry did not get his annulment, he tried to take control of the church in England. More could not agree with Henry on this point because More felt strongly that the pope should remain in control of the whole church. Because of this, he resigned as chancellor in 1532. Henry could not tolerate his opposition and had him executed for treason in 1535.
Thus, the answer to your question is Sir/Saint Thomas More.