Herupeys, Hirelgas, Hirelglas, Hireslglas
Nephew of Bedivere and a knight of Arthur’s court in Geoffrey of Monmouth’s Historia.
During the Roman War, he saw his uncle killed by King Boccus of Media, and he became enraged. He avenged Bedivere’s death by slaying Boccus.
The French Liber de Compositione Castri Ambaziae renames him Billeius and the Vulgate Merlin calls him Segart.
Sources
Historia Regum Britanniae | Geoffrey of Monmouth, c. 1138
Roman de Brut | Wace, c. 1155