John Fisher (born 1469, died 1535) was an English prelate, who, devoted to the Pope and to the Roman Catholic church, resisted King Henry VIII of England by refusing to recognize royal supremacy and the abolition of papal jurisdiction over the English church.

He was ordained a priest in 1491. In 1504 he was appointed Chancellor of Cambridge University and consecrated as Bishop of Rochester, Kent.

His books in Latin against Lutheranism gave him a European reputation as a theologian. He strongly opposed any state interference in church affairs, urging that the church should reform itself. When the validity of the marriage between Henry VIII and Catherine of Aragon was first openly questioned in 1527, Henry and Cardinal Wolsey consulted Fisher; he incurred the king’s wrath when he defended Catherine in 1529, later publishing his defense and preaching in London on the queen’s behalf. In 1531 he vehemently opposed the granting to Henry of the title “Supreme Head of the Church and Clergy of England” and subsequently repudiated the Supremacy Act of 1534.

The passing of the Supremacy and Treason acts at the end of the year made denial of the royal titles treasonable. On May 20, 1535, Pope Paul III created Fisher a cardinal. He was called several times before councilors but refused to speak about the supremacy. He was tried on June 17, condemned for treason and on June 22 was martyred on Tower Hill.

In 1934, Pope Pius IX Canonized Cardinal Fisher a saint. He and St. Thomas More share a feast day on the 22nd day of June.