John Cornelius was born at Bodmin of Irish parents.
He became a fellow of Exeter College, Oxford, and a student at Rheims and then at Rome, where he was ordained a priest in 1583.
He worked for ten years on the English mission at Lanherne and became a Jesuit only in 1594.
The Act of 1585 made it high treason to have been ordained a Roman Catholic priest and simple treason to aid a priest. The penalty for laypeople dealing with the outlawed priest was liable to vary according to local custom--some may have gotten off fairly lightly. On the other hand, a man might be hanged for buying a priest a tankard of ale.
Thomas Bosgrave was a gentleman, the nephew of Sir J. Arundel. Martyred with Cornelius and Bosgrave were two of Bosgrave's servants: John Carey and Patrick Salmon. They were accused of sheltering priests.
John Cornelius was condemned for his priesthood. Thomas Bosgrave had taken off his hat and crammed it on the head of Mr. (Father) Cornelius, when the Jesuit was being carried away as a prisoner-- "The honour I owe to your function may not suffer me to see you go bareheaded." Mr. Bosgrave was instantly arrested, led away, and hanged together with Mr. Cornelius.
(Note: At that time in England, priests were addressed 'mister.' It was not until the mid-19th century that the Irish Catholic practice of using 'father' became customary in England)
Died at Dorchester, England, 1594
Beatified in 1929.