Edward II gave Builth to his wife Isabella, who leased it to Roger Mortimer and thereby established their connection. Mortimer later became Isabella's lover and supported her coup against Edward II, which ended with the deposed king's death. When Edward III reached adulthood in 1330, he arranged the capture of Isabella and Mortimer, had Mortimer executed for treason, and seized his properties. Gilbert Talbot, the Justiciar of South Wales, then took Builth.
Chapter · 4:56-6:13
Mortimer, Isabella, and Edward III
Builth's ownership becomes entangled with Isabella, Roger Mortimer, Edward II's fall, and Edward III's recovery of royal authority.