A town in the southwest of Messenia, was situated at the foot of Mount Aegaleos on a promontory at the northern entrance of the basin, now called the Bay of Navarino, the largest and safest harbour in all Greece. This harbour was fronted and protected by the small island of Sphacteria (Sphagia), which stretched along the coast about 1 3/4 miles, leaving only two narrow entrances at each end.

Pylos became memorable in the Peloponnesian War, when the Athenians under Demosthenes built a fort on the promontory Coryphasium a little south of the ancient city, and just within the northern entrance to the harbour (B.C. 425). The attempts of the Spartans to dislodge the Athenians proved unavailing; and the capture by Cleon of the Spartans who had landed on the island of Sphacteria was one of the most important events in the whole war ( Thuc.iv. 3-13; 29-40). (Harpers Dictionary of Classical Antiquities, 1898)