Jupiter in Britain
Jupiter Optimus Maximus was the head of the Roman pantheon and main deity of the official Roman state religion, the Capitoline Triad. Jupiter (IOM) was the main deity worshipped by the army. Each unit had to swear allegiance to the emperor and the Roman government by dedicating each New Year an altar to him.
Jupiter dedications can be placed into three categories: IOM, IOM and other deities, and IOM Dolichenus. There are 82 IOM altars, 29 IOM and other deities, and 15 IOM Dolichenus altars in Roman Britain with 54 IOM altars, 9 altars to IOM and other gods, and 5 IOM Dolichenus altars in Cumbria. Most fort sites have at least one or two IOM altars, but in Cumbria there are several sites that have ten or more altars. Those sites are Maryport, and Birdoswald, while there are seven at Castlesteads and Old Carlisle. Cumbria has more altars then the rest of the province because a large portion of the population in the north was military. These altars give us insight into what units were stationed during the Roman occupation in the north.
One interesting point about Jupiter though is he was never equated with a Celtic counterpart in Roman Britain, but he is named jointly with Celtic gods. There are two examples from Britain I want to point out. The first example is an altar from Binchester (RIB 1030) where IOM and Deae Matres Tramarinae are named by the dedicator, a beneficiarius of the governor, for the well being of himself and his household. The second example is an altar from Housesteads (RIB 1583) where legionaries of the second Augusta dedicated to IOM along with Cocidius and the Genius Loci.
You do not tend to find altars dedicated to IOM from civilians and there is only one altar from Cumbria that is set up by civilians. The altar comes from Old Carlisle (RIB 899) and they are dedicated to the emperor from money the vicani collected themselves.
