Hibernia, in ancient geography, one of the names by which Ireland was known to Greek and Roman writers. Other names were Ierne, Iouernia and (H)iberio. All these are adaptations of a stem from which Erin and Eire are also derived. The island was known to the Romans through the reports of traders, so far at least as its coasts, but never became part of the Roman empire. In approximately 80 ce Agricola planned its conquest from Britain, which he judged easy, but the Roman government forbade it. During the Roman occupation of Britain, Irish pirates seem to have been an intermittent nuisance, and Irish emigrants may have settled occasionally in Wales. It was only after the decline of Roman Britain that Christian missionaries, such as St. Palladius and St. Patrick, attempted to bring the island into the Roman sphere.