the peninsula formed part of the roman geographical area of armorica. the town known today as coutances, capital of the unelli, a gaulish tribe, acquired the name of "constantia" in 298 during the reign of roman emperor constantius chlorus. the base of the peninsula, called in latin the "pagus constantinus", joined together with the "pagus coriovallensis" centred upon cherbourg to the north, subsequently became known as the cotentin. under the carolingians it was administered by viscounts drawn successively from members of the saint-sauveur family, at their seat saint-sauveur on the douve.