Ionic or Ionian Greek was a subdialect of the Eastern or Attic–Ionic dialect group of Ancient Greek. The Ionic group traditionally comprises three dialectal varieties that were spoken in Euboea, the northern Cyclades, and from c. 1000 BC onward in Asiatic Ionia, where Ionian colonists from Athens founded their cities. Ionic was the base of several literary language forms of the Archaic and Classical periods, both in poetry and prose. The works of Homer and Hesiod are among the most popular poetic works that were written in a literary form of the Ionic dialect, known as Epic or Homeric Greek. The oldest Greek prose, including that of Heraclitus, Herodotus, Democritus, and Hippocrates, was also written in Ionic. By the end of the 5th century BC, Ionic was supplanted by Attic, which had become the dominant dialect of the Greek world.