Calgacus

According to Tacitus, Calgacus was a chieftain of the Caledonian Confederacy who fought the Roman army of Gnaeus Julius Agricola at the Battle of Mons Graupius in northern Scotland in AD 83 or 84. Some older scholarship has proposed a Brittonic derivation, *calg‑ac‑os, meaning 'possessing a blade' or 'swordsman', but this interpretation is highly speculative and not attested in contemporary source