Ambrosius Timeline and Summary

Ambrosius interrupts Uther as he's about to beat Merlin to death and takes the boy home. He gives Merlin Cadal as a servant and Belasius as a tutor.
Ambrosius prepares his troops for an eventual takeover of Britain.
When Merlin gets in trouble for hanging out around the druids, Ambrosius talks with him. He reveals that Merlin is his son. Merlin reveals that Ambrosius will be High King of Britain.
Ambrosius sends Merlin back to Wales to get some intel and help with the timing of the invasion.
When he learns that Vortigern is picking on his son, Ambrosius rushes over. At Doward, Ambrosius burns Vortigern and his wife to death in their tower.
Ambrosius' army chases Hengist down and engages him at Kaerconan. Merlin joins Ambrosius there and tells him that Niniane is dead.
Ambrosius defies the bishop by giving Hengist a Saxon funeral but then appeases him by having a Christian victory celebration.
Ambrosius asks Merlin to reset Stonehenge as a memorial to those killed by Hengist, but after Merlin basically tells him he's going to die, Ambrosius also requests to be buried there.
While Merlin is on his way home from Ireland, Ambrosius is poisoned and dies. He is buried at Stonehenge.