Druidical worship. Druid priest (centre left) on top of a dolmen, holding a sickle and engaging in a ceremony involving the Full Moon (upper centre). The druids were a Celtic priestly class that existed in western Europe (Britain, Ireland and Gaul), from at least the Iron Age up into Roman times when the practice was suppressed. The Celts, led by the druids, practiced forms of pagan nature worship, revering the Sun, Moon and stars. Dolmens are the remains of megalithic Stone Age tombs. This artwork, by French illustrator Leon Benett (1838-1917), is from Astronomical Myths (1877) by the British geologist John Frederick Blake (1839-1906).