Branwen spent years in imprisonment in Ireland — serving for the crimes of her half-brother, during which time she used her charms to befriend a starling.
Ar ôl iddi orfod priodi Matholwch er lles y wlad, treuliodd Branwen flynyddoedd dan glo yn Iwerddon, oherwydd troseddau’i hanner brawd, Efnisien.