[2] Llywelyn is thought to have been born before 1267,[1] as Gruffudd was dispossessed of the lordship of Senghenydd in that year by Gilbert de Clare, 7th Earl of Gloucester and then imprisoned in Ireland.
The Battle of Bannockburn in June 1314 marked the death of Gilbert de Clare, 8th Earl of Gloucester the Lord of Glamorgan.
That combined with the death of several hundred men of Glamorgan at Bannockburn caused a revolt in the lordship in late summer that year.
The revolt appears to have ended when King Edward II of England appointed Bartholomew de Badlesmere, as royal custodian in Glamorgan.
[citation needed] Bren was called "Son of death" by the King of England, and summoned to Lincoln for 27 January 1316, but secretly fled home, and had no problems starting a revolt with the general discontent throughout Wales.
In 1317, Llywelyn became the prisoner of the ruthless Hugh Despenser the Younger,[2][3] one of King Edward's favourites at court, who had become Lord of Glamorgan in November 1317.
[citation needed] As antipathy to the Despensers grew, Llywelyn's death united the native Welsh and Marcher Lords.
[3] Barons under the Earl of Hereford and others like Hugh Audley and Roger d'Amory petitioned the king to dismiss and exile the Despensers; the murder of Llywelyn Bren was prominent on their list of complaints.
When the king refused, an alliance of local Welsh men and Marcher Lords raided Despenser's lands in Glamorgan for some ten days.
Edward had to exile the Despensers until he gathered forces to defeat the barons at the Battle of Boroughbridge in 1322, where the Earl of Hereford died.
[8] With the Despensers' return to Edward's court, Lleucu and her sons were again imprisoned, this time in Bristol Castle, but their actions soon aroused more resistance.
In October 1326, a successful rebellion led by Roger Mortimer gave the Despensers and Edward further cause to regret their actions in Glamorgan after being forced to flee there.