'Blue-black', 'Black stream' | Dubglas, Duglas
A river in Britain which was, according to Nennius, the site of Arthur’s second, third, fourth, and fifth battles against the Saxons. When the new king, aged just fifteen and having newly ascended the throne, defeated the Saxon leader Colgrin and a mixed force of Saxons, Scots and Picts. Colgrin took refuge after the fourth battle in York, and Arthur then laid siege to him there.
There are scattered rivers with similar names in Scotland, including a Dunglas in Lothian, which may be meant by Linnuis, but it is unlikley that Arthur would have fought the Saxons so far north. He may have been fighting Picts. Geoffrey of Monmouth includes the fight - condensing Nennius’s four battles into one - and seems to identify it with the River Duglas in Lancashire. The Saxons fled to the nearby city of York after their defeat.
Glas is used to denote azure, green, blue. When applied to water it signifies blue, but when applied to land it means green.
Glas | Notes | The Knight of the Round Table