According to the Catholic Encyclopedia:
English martyr, b. at Ghisburn, Yorkshire; executed at York, 24 September, 1589. His maternal uncle, William Horn, who signed for the Rectory of Cornwell, Oxfordshire, in 1559, sent him in 1573 to Trinity College, Oxford, where he became Fellow in 1579 and M.A. in 1580. There, convinced of the truth of Catholicism, he used his position to influence his pupils in that direction; but he delayed his reconciliation till 1582, when, with four other Trinity men (John Appletree, B.A., already a priest; William Warford, M.A. and Fellow, afterwards a Jesuit; Anthony Shirley, M.A. and Fellow, afterwards a priest; and John Fixer, B.A., afterwards a priest), he embarked from the Isle of Wight, and landed near Cherbourg, arriving at Reims, 2 November. Received into the Church five days later, he was ordained sub-deacon and deacon at Laon by the bishop, Valentine Douglas, 7 April, 1583, and priest at Reims by the Cardinal Archbishop de Guise, 24 September, and was sent on the mission 29 August, 1584. He effected the reconciliation of his parents and his uncle (the latter was living as a Catholic priest in 1593), and afterwards voluntarily immured himself in York Castle to help the prisoners there. He was condemned under 27 Elizabeth, c. 2, merely for being a priest. With him suffered a layman, Robert Hardesty, who had given him shelter.
Blesseds Spenser and Hardesty were among the 85 Martyrs of England and Wales beatified by Blessed Pope John Paul II in 1987. A Catholic Herald article at the time highlighted the number of Catholic laymen included among the 85, noting:
These laymen died because they believed that it was the mass that mattered, because they believed in the priesthood, and because they believed in the authority of St Peter's successors, rather than in the claims of Henry VIII (sic), and Queen Elizabeth I, who personally signed and approved each of their sentences of death.
No amount of white-wash or fudging can get round the fact that the stark simple faith of these laymen, most of whom met the most barbaric of deaths, along with 63 (sic) martyr priests, helped to keep the Faith alive at a time when Henry VIII and Elizabeth I thought that they had blotted it out for ever.