John is one of the “Surety Barons” named for the enforcement of the Magna Carta signed by King John of England in 1215.

Lord of Warkworth Castle
High Sheriff of Northumberland
Governor of New-Castle-upon-Tyne

JOHN FITZROBERT, the Surety, married Ada Baliol, and in her right became lord of Barnard Castle, whose founder was Barnard Baliol.

When the Barons met at Saint Edmondsbury, John FitzRobert, the Surety, was still loyal to King John and was, with John Marshall, joint governor of the Castles of Norwich and Oxford. Subsequently he joined the insurrection, and took such a prominent part that his lands were seized by the King. He returned allegiance in the next reign, his Castles and vast estates were returned to him, and he was constituted high sheriff of co. Northumberland and governor of New-Castle-upon-Tyne. He died in 1240, the same year as his father. The monk, Matthew Paris, records: "In this year died John FitzRobert, a man of noble birth, and one of the chief Barons of the Northern provinces of England."