This device did not appear on their coat of arms, (az, a bend ar cotised or, between 6 lioncels or) nor their crest (gu, doubled erm, a lion gardant crowned), but it does appear on Humphrey's personal seal (illustration).

In one of the campaigns in Scotland Humphrey evidently grew bored and departed for England to take part in a tournament along with Piers Gaveston and other young barons and knights.

Between the time that he swore his last fealty to Edward I in 1302 and his defection four years later, Bruce stayed for the most part in Annandale, rebuilding his castle of Lochmaben in stone, making use of its natural moat.

However, since the execution of Piers Gaveston in 1312, Humphrey had been out of favour with Edward II, who gave the Constableship for the 1314 campaign to the youthful and inexperienced Earl of Gloucester, Gilbert de Clare.

When the battle was lost, Bohun retreated with the Earl of Angus and several other barons, knights and men to Bothwell Castle, seeking a safe haven.

However, all the refugees who entered the castle were taken prisoner by its formerly pro-English governor, Walter fitz Gilbert, who, like many Lowland knights, declared for Bruce as soon as word came of the Scottish King's victory.

[2] Like his father, grandfather, and great-great-grandfather, this Humphrey de Bohun was careful to insist that the king obey Magna Carta and other baronially established safeguards against monarchic tyranny.

The subsequent revival of royal authority and the growing ascendancy of the Despensers (Hugh the elder and younger) led Bohun and other barons to rebel against the king again in 1322.

[5] His marriage to Elizabeth of Rhuddlan daughter of King Edward I of England and his first wife, Eleanor of Castile, on 14 November 1302, at Westminster gained him the lands of Berkshire.

Until the earl's death the boys of the family, and possibly the girls, were given a classical education under the tutelage of a Sicilian Greek, Master "Digines" (Diogenes), who may have been Humphrey de Bohun's boyhood tutor.

[citation needed] He was evidently well educated, a book collector and scholar, interests his son Humphrey and daughter Margaret (Courtenay) inherited.