Awarded a doctorate by the University of Oxford 1520, he became canon of Windsor 1520–49, Prebendary of Lincoln Cathedral 1522–48, paymaster of the forces and treasurer of the wars in the north 1523, and custodian of St Leonard's Hospital, York 1529.
"[3] Magnus died on 18 August 1550, and is buried in Sessay in the North Riding of Yorkshire, his epitaph reads "Here lyeth Mr Thomas Magnus, arch-deacon of the East Riding in the metropolitan church of York, and parson of this church, which died the 18th day of August, anno domino 1550, whose soul God pardon.
"[4] After waiting at Newcastle for instructions from Henry VIII and Wolsey, and a Scottish safe-conduct, Magnus and Roger Radclyff arrived in Edinburgh on 29 October 1524.
After mass, Magnus and Radclyff gave James a sword and a coat of cloth-of-gold, gifts from Henry VIII.
[5] Magnus visited Margaret Tudor at Perth in March 1525, bringing certain news of the defeat of Francis I of France at Pavia and a letter from Henry VIII that made her weep uncontrollably for an hour.