From across the narrow channel that separates the island from the Peloponnese, Poros still has the appearance, in the early morning light, of a watercolour scene by a 19th century traveller such as Edward Lear. The timeless charm of the island has been well conserved, with its picturesque architectural uniformity, the simple harmonious forms against the back-drop of pine-clad mountains—white and red against green—and the constant, unobtrusive activity of boats and cai―ques in its placid waters. The land scape is typically Peloponnesian, just as that of Salamis is typically Attic. Though small, the island has always had a certain strategic importance. In early antiquity the sanctuary of Poseidon on the island’s central mountain was the focus of the Calaurian League, a confederation of important cities which included Athens and Aegina amongst others, all of whom were bound by a common need to pay due respect to the god of the waters on whom their life depended. The archaeologically explored area of Calauria and its sanctuary is still limited, but its panoramic setting is beautiful. Two and a half thousand years later, Poros was again a maritime centre and home to the first naval headquarters of independent Greece. The wealth that maritime trade has brought to the island is reflected in its dignified architecture.
The island is small and little built-up, making it easy to explore on foot or by bicycle; its waters are clean and its shaded coves a pleasure to bathe in. The town is compact and busy and, because of the ease of access from Piraeus, can occasionally flood with visitors during the day. But the mainland opposite, with its contrasting vastness, lies only 250m away and offers much of interest, both in history (Ancient Troezen) and in landscape (the monumental citrus groves of Galatas, and the dramatic Methana peninsula).
Changes in the levels of water and land in what is a seismically very active area (witness the volcanic cone of Methana visible to the northwest) have altered the geographical configuration of Poros. Today the island consists of two parts: the small, volcanic island of Sphairia (named after Sphaeros, the charioteer of Pelops) occupied by the town of Poros; and the main, mountain ous body of the island, called Calauria in Antiquity, to its north. These are joined by a swampy isthmus today, but were separated by water in ancient times. The name ‘Poros’ means ‘crossing’ or ‘ford’. Sphairia, on the other hand, was originally joined to the Peloponnesian main land until seismic subsidence in Late Antiquity sundered it and created the shallow channel (only 250–300m wide) between Galatas and Poros. The islet of Sphairia in effect ‘changed sides’. All this activity has resulted in a landscape of particular beauty, embellished by the simple, dignified architecture of 19th and early 20th centuries, set amidst pine-clad slopes and stretches of open water.
Poros Island is part of the Argosaronic Island Group, Greece.