John Aylmer (1521-1594), English divine, was born in the year 1521 at Aylmer Hall, Tivetshall St Mary, Norfolk. While still a boy, his precocity was noticed by Henry Grey, marquis of Dorset, afterwards duke of Suffolk, who sent him to Cambridge, where he seems to have become a fellow of Queens' College. About 1541 he was made chaplain to the duke, and tutor to his daughter, Lady Jane Grey. His first preferment was to the archdeaconry of Stow, in the diocese of Lincoln, but his opposition in convocation to the doctrine of transubstantiation led to his deprivation and to his flight into Switzerland. While there he wrote a reply to John Knox's famous Blast against the Monstrous Regiment of Women, under the title of An Harborowe for Faithfull and Trewe Subjects, etc., and assisted John Foxe in translating the Acts of the Martyrs into Latin. On the accession of Elizabeth he returned to England. In 1559 he resumed the Stow archdeaconry, and in 1562 he obtained that of Lincoln. He was a member of the famous convocation of 1562, which reformed and settled the doctrine and discipline of the Church of England. In 1576 he was consecrated bishop of London, and while in that position made himself notorious by his harsh treatment of all who differed from him on ecclesiastical questions, whether Puritan or Papist. Various efforts were made to remove him to another see.
He is frequently assailed in the famous Marprelate Tracts, and is characterized as "Morrell," the bad shepherd, in Spenser's Shepheard's Calendar (July). His reputation as a scholar hardly balances his inadequacy as a bishop in the transition time in which he lived. He died in June 1594. His Life was written by John Strype (1701).