About Aurelianus Ambrosius
Ambrosius Aurelianus (Welsh, Emrys Wledig); called Aurelius Ambrosius in the Historia Regum Britanniae and elsewhere, was a war leader of the Romano-British who won an important battle against the Anglo-Saxons in the 5th century, according to Gildas. He also appeared independently in the legends of the Britons, beginning with the 9th-century Historia Brittonum.
A contested ancestry
Tradition is firm that he was brother of Uther Pendragon. However, there are many differing traditions and reconstructions of ancestry, including the following: