Who is Commius from The Conquest of Gaul and what is their importance?

Commius is the King of the Atrebates. Caesar has elevated him to this position after subduing the Atrebates because he thought highly of his courage and loyalty. When Caesar returns the hostages that the Britons have sent him before his first invasion, they are accompanied by Commius, who is instructed to find out as much as possible about the British tribes. On other occasions, Caesar uses him as an intermediary or even to keep tribes like the Menapi under surveillance. As a reward for his services, Caesar exempts the Atrebate from taxes and makes Commius ruler of the Morini.