Ambrosius Aurelianus

   In Nennius, Ambrosius was the fatherless child whom Vortigern intended to sacrifice. Geoffrey of Monmouth, however, maintained that Ambrosius the child was Merlin Emrys and distinct from Ambrosius Aureli(an)us.
   In later legend, Ambrosius Aurelianus was the uncle of Arthur. Born to the purple and forced to flee when his father Constantine was killed and Vortigern used and then killed his brother Constans, he returns with his brother Uther to exact revenge and reclaim his heritage. He laid siege to Vortigern's tower and burnt it down, thereby causing Vortigern's death. With his brother, they defeated the Saxons and had their leader, Hengist, killed. Ambrosius commissioned Merlin to bring the Giant's Dance from Ireland and create a monument to the fallen at Stonehenge (a curious but false legend owing something to the true fact that a number of the sarsen stones were transported from a distance to Stonehenge) Paschent, Vortigern's son, made war against him and had him poisoned by a Saxon, Eopa.
   It has been noted and discussed by many that Gildas does not mention Arthur but states that Ambrosius was the victor at Badon. Some have stated that the connection was not direct and that Gildas did not mention Arthur, who is later attributed as the victor at Badon, for many reasons. This has led some investigators to claim that either Gildas did mention Arthur, but by his real name, or that Arthur was Ambrosius' warlord (or in fact, Uther, his brother, is not Uther but Uthyr a cognomen for his warlord/ brother which would later become Arthur, i.e. nicknames at different points in a person's life).