According to Julius Caesar, of all the gods Celts revered Mercury the most, regarding him as the inventor of all arts. The cult of Mercury became widespread not only in Roman Gaul, which was one of the most thoroughly Romanised provinces of the Empire, but also in Roman Britain — the farthest western area governed by the Roman Empire. In both provinces Mercury was worshipped as the patron of commerce, which befitted him as the Roman god of trade and profit. At the same time, in both Gaul and Britain Mercury was syncretized with the Celtic horned god of fertility. Archaeological findings from these regions also suggest that the Mercury worshipped in Britain and Gaul during the Roman rule was also the guardian of military affairs — a role absolutely untypical of the original Roman god, but necessary for the supreme god of Celts who was the divine warrior-patron of Celtic tribes. Besides, the magical-chthonic aspect of Celtic Mercury likened him to Hermes, the god of eschatological and mystical endeavour of humankind in the religion of the Ancient Mediterranean.