When the traveller and geographer Pausanias left Athens towards Eleusis, he knew that he may have had to face a mighty obstacle. Just before he reached the sanctuary of Demeter, he would inevitably come across a river. He minced no words when he later described it: “At Eleusis flows a Cephissus which is more violent than he Cephissus I mentioned above”. This was no place for unsuspecting visitors. When Pluto, the lord of the Underworld, abducted Persephone, he descended to his gloomy realm from here; the banks of the Cephissus was also the site selected by Procrustes, the infamous bandit who killed his victims by stretching them or cutting off their legs so as to force them to fit the size of his bed.
In classical antiquity, Eleusis had no reason to fear Pluto (at least not more than any other mortal anywhere on the earth) or Procrustes (who made a mortal mistake when he tried to make Theseus fit to his terrible bed). But the town was exposed to dangerous inundations. The Eleusinian Cephissus was a fast flowing river which formed from the contributions of several streams that originated in western Mount Parnitha and eastern Cithaeron. The river passed through the Thriasian Plain and would occasionally flood a large part of the plain, especially the southwestern region near Eleusis.
The great Athenian orator Demosthenes singled out Cephissus as an example of a particularly destructive river that tended to flood the farms along its course after torrential rains. The loss of property and crops as a consequence of an inundation which occurred during the winter he was spending in Athens convinced Emperor Hadrian to finance the erection of embankments; the remains of two ancient mounds seen by members of the Society of Dilettanti and the English topographer and writer William Martin Leake (1777-1860) in the early 19th century probably belonged to Hadrian’s embankment.
Sudden floods were a problem for the pilgrims as well. The people who visited the sanctuary of Demeter had to cross the river approximately one kilometre east of Eleusis. During most of the year, the water level was low enough to enable them to cross without much difficulty. But when it rained or the river flooded, the crossing was dangerous. In the last quarter of the 4th century BCE, a man called Xenocles constructed a stone bridge to ensure the safety of the pilgrims and the people of Eleusis. The bridge must have been damaged at some point, because in 124 or 125 CE when Hadrian ordered the erection of the embankments, there was no bridge across the river Cephissus. The Emperor, who was initiated into the Eleusinian Mysteries that year, decided to construct a new bridge.
The stone bridge had a total length of 50 meters and its width was 5.30 meters. The central part consisted of a 30-meter long section over the river and two 10-meter long access ramps on either end. The main bridge rests on four arches; the two inner arches are wider than the ones at the edges (6.90 meters compared to 4.30 meters). The piers are protected by semi-cylindrical buttresses to resist the fast-flowing current. The architects further reinforced the bridge by laying large rectangular blocks of hard limestone from Piraeus on the riverbed. Two powerful stone walls were added upstream to control the flow of the water. The workmanship is superb and enabled the bridge to survive largely intact to the present day.
It was the quality of the construction that initially confused the researchers who tried to date the bridge. The Greek archaeologist Dimitrios Filios (1844-1907), who noticed the remains of the bridge in 1892, next to a water hole locally known as the “Pleasant Well”, believed that this was the stone bridge of Xenocles. In was only in 1950, after the careful study of the bridge, that the architect and archaeologist Ioannis Travlos (1908-1985) was able to determine conclusively that the structure was Roman. The type of metal ties between the stone blocks, the occasional use of mortar, and the presence of Latin numerals and stonemasons’ marks that resembled those found on Hadrian’s Library in Athens convinced Travlos that this was the bridge donated to the people of Eleusis by the Roman emperor.
During the Byzantine period, a rectangular tower was built on the central section of the bridge, that was still visible above the ground. The tower enabled its occupants to control traffic on the ever-important road that connected Athens to Megara, Thebes, and Corinth. As for the river, its course shifted over the centuries and the riverbed was slowly filled in. The old name was forgotten and the torrent was known as Sarantapotamos (“Forty Rivers”). Today, the once mighty river is a mere brook that remains dry during the greater part of the year.