Ambrosius Aurelianus (; Anglicised as Ambrose Aurelian and 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. Eventually, he was transformed by Geoffrey of Monmouth into the uncle of King Arthur, the brother of Arthur's father Uther Pendragon, as a ruler who precedes and predeceases them both. He also appears as a young prophet who meets the tyrant Vortigern; in this guise, he was later transformed into the wizard Merlin. According to Gildas Ambrosius Aurelianus is one of the few people whom Gildas identifies by name in his sermon De Excidio et Conquestu Britanniae, and the only one named from the 5th century. De Excidio is considered the oldest extant British document about the so-called Arthurian period of Sub-Roman Britain. Following the destructive assault of the Saxons, the survivors gather together under the leadership of Ambrosius, who is described as: Some basic information on Ambrosius can be deduced from the brief passage: Ambrosius was possibly of high birth and very likely a Christian (Gildas says that he won his battles "with God's help"). Ambrosius's parents were slain by the Saxons and he was among the few survivors of their initial invasion. According to Gildas, Ambrosius organised the survivors into an armed force and achieved the first military victory over the Saxon invaders. However, this victory was not decisive: "Sometimes the Saxons and sometimes the citizens [meaning the Romano-British inhabitants] were victorious." Due to Gildas's description of him, Ambrosius is one of the figures called the Last of the Romans. Scholarship questions Two points in Gildas's description have attracted much scholarly commentary. The first is what Gildas meant by saying Ambrosius' family "had worn the purple". Roman emperors and male Patricians wore clothes with a purple band to denote their class so the reference to purple may be to an aristocratic heritage. Roman military tribunes (tribuni militum), senior officers in Roman legions, wore a similar purple band so the reference may be to a family background of military leadership. The tradition was old, as the togas and pallia of already ancient senators and tribunes were trimmed with the purple band. In the church, "the purple" is a euphemism for blood and therefore