Addedomarus (sometimes written Aθθedomarus on coins) was a king of south-eastern Britain in the late 1st century BC.

He seems to have moved the Trinovantian capital from Braughing in Hertfordshire to Camulodunum (Colchester, Essex).

15–10 BC) he seems to have been supplanted by Tasciovanus of the Catuvellauni, who issued coins from Camulodunum at that time.

Addedomarus then appears to have regained power and reigned until 10–5 BC, when he was succeeded by Dubnovellaunus.

[3][4][5] The Welsh Triads recall Aedd Mawr as one of the founders of Britain.