Beulan
From BiblePortal Wikipedia
Beulan [1]
a British divine and historian of the 7th century, was the instructor of the celebrated Nennius, afterwards abbot of the monastery of Bangor. He is said to have written a work entitled De Genealogiis Gentium. See Allibone, Ῥ Dict. Of Brit. And Amer. Authors, s.v.; Chalmers, Biog. Dict. s.v.