Thule

To the west, beyond even Britannia, was Hibernia (Ireland). Caesar speaks of it as being half the size of Britain and lying at the same distance from it as does Gaul. Tacitus, too, writes that it is smaller than Britain, but that the character and civilization of its inhabitants are much the same, and that its ports are conveniently situated for trade with Gaul. More ominously, its conquest by Agricola would offer no refuge for the rebellious tribes of Britannia "if Roman arms were in evidence on every side and liberty vanished off the map." Strabo also speaks of Ireland, as do Pomponius Mela, Pliny, Ptolemy, and Julius Solinus, who says that it has no snakes.

Thule, a mysterious land to the north, first was reported by Pytheas, a Greek sailing from the colony of Massalia (Marseille) in the fourth century BC. The place never was discovered by other mariners, and, consequently, his account is referred to by later writers with considerable misgiving. It may have been Iceland or even Norway. By the first century BC, the word had become an expression for the furthest place on earth; Strabo, for instance, identifies the Shetland Islands as Thule.