CEOS (K∈ως), the modern Zea or Tzia, an island in the Aegean Sea, belonging to the group of the Cyclades and the eparchy of Syra, 14 miles off the coast of Attica. Its greatest length is about 13 miles, and its breadth about 8. It gradually rises towards the centre, where it culminates in Mount Elias, 1860 feet high. Among its natural productions are lemons, citrons, olives, wine, and honey; and it also exports a considerable quantity of valonia. There were formerly four towns of some importance in the island :—Iulis, about three miles from the north-west shore; Coressia, the harbour of Iulis, with a temple of Apollo Smintheus in the neighbourhood; Carthaea in the south-east; and Poieëssa in the south-west. Of these Iulis is represented by the town of Zea, and Carthaea by the village of ’S tais Polais; and traces of the other two can still be made out. In ancient times Iulis was the birthplace of the lyric poets Simonides and Bacchylides, the philosophers Prodicus and Ariston, and the physician Erasistratus; and the excellence of its laws was so generally recognized that the title of Cean Laws passed into a proverb. One of them, which forbade a citizen to protract his life beyond sixty years, affords a curious instance of the application of utilitarian principles. The present population of the island is about 8000, of which the capital has about 4300.