Question: Ambrosius Aurelianus as a war leader of the Romano-British who won an important battle in the 5th century, according to a 6th-century British monk best known for his scathing religious polemic which recounts the history of the Britons before and during what? 
Sentence (from "Ambrosius Aurelianus"): He also appeared independently in the legends of the Britons, beginning with the 9th-century "Historia Brittonum".
Relevant evidence: No