Ebrauc, Efrawg, Efrog
A legendary King of Britain and the sixth king after Brutus, he ascended the throne after his father, Mempricius, was killed by wolves. Ebraucus reigned for 39 years, he was admired, very strong and tall, according to Geoffrey of Monmouth. H
His rule was said to have started in 944 BC, when he plundered Gaul and founded the city of York, which was named after him, Dumbarton and Mount Agned. The Romans called this city Eboracum when they captured it from the Brigantes in AD 71 and made it their northern headquarters.
Ebrauc was also alleged to have founded Edinburgh and to have had twenty wives, twenty sons and thirthy daughters. All his children, except for Brutus II Greenshield (who succeeded him), were sent to either his cousin, Silvius Alba in Alba Longa, western Italy, or to Germany.
Arthurian legends made him the founder of the Castle of Maidens, which was originally known as the Castle of Mount Agned.
Source
Historia Regum Britanniae | Geoffrey of Monmouth, c. 1138