John of Brittany served England as a soldier and as a diplomat but was otherwise politically inactive in comparison to other earls of his time.

Although he was generally loyal to his first cousin Edward II during the times of baronial rebellion, he eventually supported the coup of Isabella and Mortimer.

[5] His father held the title of Earl of Richmond, but was little involved in English political affairs.

[10] In January 1297 he shared defeat at the Siege of Bellegarde with Henry de Lacy, Earl of Lincoln.

[11] Despite his poor results in France he remained highly regarded by his uncle King Edward I, who treated him almost as a son.

[c][d] In this roll, the banner and description of John of Brittany immediately follows that of his uncle King Edward I.

[16] John was allegedly Gaveston's close personal friend, and did not share the antagonistic attitudes held by certain other earls.

The earls disobeyed a royal order not to carry arms to parliament, and in full military attire presented a demand to the king for the appointment of a commission of reform.

At the heart of the deteriorating situation was the peers' opinion of Edward II's relationship with Piers Gaveston, and his reputedly outrageous behaviour.

[20] It fell upon John, together with Gilbert de Clare, Earl of Gloucester, to reconcile the two parties after this event.

All that stood between them and a royal prize was a large English force under the command of John of Brittany.

To dislodge John from his strong position on the high ground, Bruce used the same tactics that brought victory at the earlier Battle of the Pass of Brander.

He spent his last years on his French estates, and he remained largely cut off from English political affairs.