Éire (ˈeːɾjə) is Irish for "Ireland", the name of both an island in the North Atlantic and the sovereign state of the Republic of Ireland which governs 84% of the island's landmass. The latter is distinct from Northern Ireland, which covers the remainder of the northeast of the island. The same name is also sometimes used in English (ˈɛərə ). The modern Irish Éire evolved from the Old Irish word Ériu, which was the name of Ireland and of a Gaelic goddess. Ériu is generally believed to have been the matron goddess of Ireland, a goddess of sovereignty, or simply a goddess of the land. Ériu has been derived from reconstructed Archaic Irish *Īweriū, and further from the Proto-Celtic *Φīwerjon- (nominative singular Φīwerjū). This suggests descent from the Proto-Indo-European *piHwerjon- ("fertile land" or "abundant land"), from the adjective *piHwer- ("fat") – cognate with Ancient Greek píeira and Sanskrit pīvarī, ("fat, full, abounding"). The Archaic Irish form was borrowed into Ancient Greek. During his exploration of northwest Europe (circa 320 BCE), Pytheas of Massilia called the island Ierne (written Ἰέρνη). The Pseudo-Aristotelian text On the Universe (393b) has: Ἐν τούτῳ γε μὴν νῆσοι μέγισται τυγχάνουσιν οὖσαι δύο, Βρεττανικαὶ λεγόμεναι, Ἀλβίων καὶ Ἰέρνη. Translation: There are two very large islands in it, called the British Isles, Albion and Ierne. (modern Great Britain and Ireland). In his book Geographia (circa 150 CE), Claudius Ptolemaeus called the island Iouernia (written Ἰουερνία; ou represented /w/) and named a tribal group called the (Ἰούερνοι, Iouernoi or Iverni who lived in the southwest. This was borrowed into Latin as Hibernia. The evolution of the word would follow as such: Proto-Celtic *Φīwerjon- (nominative singular *Φīwerjū) Archaic Irish *Īweriū Old Irish Ériu Modern Irish Éire An Old Irish by-form of this placename was íriu, meaning "land, earth". In Irish mythology, Íth is the first of the Milesians (Irish) to see Ireland from Iberia.