Calagundus

Calagundus was a 1st century Briton, a prince of a "northern tribe" which was not historically meant to become involved with the Roman conquest of Britain, but were drawn into it by the War Chief.

Biography
Born in 9 AD, Calagundus was a charismatic demagogue as well as a "true zealot" of the Britons' religion, claiming on several occasions to have heard supernatural voices or otherwise received divine inspiration for the way he governed. This trend reached a climax when, (GAME: ) as part of his plot to derail the conquest, abduct Emperor Claudius, and take control of the Roman Empire, (GAME: ) the War Chief sent Sontaran recon drones mounted with holographic projectors to the leaders of various such tribes, including Calagundus's; (GAME:, ) presenting himself as a "war god" who dwelled in the Sacred Wood between Londinium and Camulodunum, he recruited these leaders into a cult of the "Inner Mysteries" and drove them to amass into a second army that would take Claudius's legions by surprise after their historically-established victory over Cattigern and Caractacus. (GAME: )

Calagundus arrived with "as many warriors as he could raise" and, because the War Chief found him particularly easy to control, he soon became the de facto leader of the alliance of tribes, instead of the otherwise-more-popular Cunovellasus. (GAME: ) Both were present in the Britons' camp when some of the time travellers who had begun to investigate the War Chief's activities were taken there; as they witnessed, he decried Princess Branimandua's words as blasphemy when she questioned the loyalties of the War Chief. (GAME: ) All of the War Chief's brainwashed victims were later freed from his control when the processing machines were smashed, allowing history to go back on track. (GAME: )

Physical appearance
Calagundus was a small but muscular man who carried himself with "absolute confidenc", his eyes perpetually "afire with fanatic zal". His beard and hair were long and tangled, and he wore a large animal's pelt over his head. (GAME: )

Behind the scenes
The Fourth Doctor short story later featured another Briton by the name of Calagundus who was active during the Roman conquest of Britain. However, this Calagundus was a young boy from the same tribe as the story's Cunovellasus, a much older druid. As such, it is doubtful that they were intended to be the same characters as their namesakes.