(Celtic: “Lord,” or “Master”), powerful Celtic deity, one of three mentioned by the Roman poet Lucan in the 1st century AD; the other two were Taranis (“Thunderer”) and Teutates (“God of the People”). Esus' victims, according to later commentators, were sacrificed by being ritually stabbed and hung from trees. A relief from the Cathedral of Notre-Dame in Paris portrays him as a bent woodman cutting a branch from a willow tree. This and a related relief from Trier, Ger., associate him with the sacred bull and his accompanying cranes or egrets.