Coal of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath), although in fact easily accessible surface coal from what became the Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal's use for iron-working in the city during the Roman period has been found. In Eschweiler, Rhineland, deposits of bituminous coal were used by the Romans for the smelting of iron ore. No evidence exists of the product being of great importance in Britain before about AD 1000, the High Middle Ages. Mineral coal came to be referred to
Sulis Minerva. Senua's name appears on votive plaques bearing Minerva's image, while Brigantia also shares many traits associated with Minerva. The identification of multiple Celtic gods with the same Roman god is not unusual (both Mars and Mercury were paired with a multiplicity of Celtic names). On the other hand, Celtic goddesses tended to resist syncretism; Sulis Minerva is one of the few attested pairings of a Celtic goddess with her Roman counterpart. Dedications to “Minerva” are common in both Great Britain and continental Europe, normally without any Celtic epithet or interpretation. (Cf. Belisama for one exception.) Based on her name's