Brien was a giant, half a foot taller than any (other?) knight in Arthur’s kingdom, yet full brother of King Bilis, who was the smallest of all dwarves and a vassal of Arthur’s.
Chrétien mentions Brien in Erec and Enide; I cannot tell whether he is named as one of the kings summoned to Erec’s wedding or merely as Bilis’ brother, nor am I sure whether or not he should be identified with Chrétien’s Briien of the double “i”.