Heptastadion

The Heptastadion (Greek: Ὲπταστάδιον) was a giant causeway, often referred to as a mole^[1] or a dyke built by the people of Alexandria, Egypt in the 3rd century BC during the Ptolemaic period.^[2] Its name comes from its length: seven stadia (Hepta meaning seven).^[3] The Heptastadion connected the mainland to Pharos Island where the Pharos lighthouse stood. The lighthouse was constructed on the orders of Ptolemy I and II, and it is probable that Ptolemy I also built the Heptastadion.^[4] The causeway formed a barrier separating Alexandria's oceanfront into two distinct harbours, with Portus Magnus (the royal harbour) to the east and Portus Eunostus (the commercial harbour) to the west.^[5] This had the advantage of protecting the harbours from the force of the strong westerly coastal current.^[6] Two channels with bridges above were let under the causeway to allow access between the two ports. Julius Caesar ordered these channels to be blocked during the Alexandrian War. The Heptastadion is also believed to have served as an aqueduct while Pharos was inhabited,^[3] and geophysical research indicates that it was part of the road network of the ancient city.^[7] Due to silting over the years,^[1] the former dyke now lies under several metres of accumulated silt and soil which form the Mansheya isthmus,^[8] upon which the Ottomans built their town from 1517 onwards.^[7]

References