The strategically-placed Isthmus of Corinth has always been of great importance for the control and the protection of the area. It is believed that even from the Mycenaean Times, efforts were made to fortify Isthmus, and the last effort being the building of the Hexamillion Wall. Herodotus refers that when Xerxes attacked the Greeks, many Peloponnesian cities asked for their soldiers to hide at Isthmus and not in Thermopylae.
The one and only pathway from the north part to Peloponnese, therefore, played a very significant role in the history of the land. The Peloponnesians repeatedly fortified the narrow pass, by building the Wall of Isthmus. Later, this constructional base was used, repaired and finally reinforced to constitute the Justinian’s Wall, which is known today as the Hexamilion Wall, because of its 6 miles long length (six : in Greek «hèxi») . It is a work of the Emperor Justine, and repaired in 1415 by the order of Michael Paleologos.
It was first built during Emperor Theodosius’ rule between 408 and 450 A.D , when the Barbarians went against the Roman Empire. There were two reasons that forced the Romans to find a solution for the fortification problem. The first was when Alarichos attacked Greece in 396 A.D., and the second when the Visigoths attacked Rome in 410 A.D. After that, the area was finally fortified and strengthened with towers and bastions.
The wall, remains of which are still visible today, was constructed during Justinian’s rule and extended along Isthmus from the shores of the Saronic Gulf until the Corinthian Gulf. It constitutes one of the biggest and most significant fortifications for the protection and defense of Peloponnese from the barbaric raids. The construction lasted from 548 until 560 A.D.
It was 7,5 km long and 3 m wide and is strengthened at intervals with quadrilateral towers, that protrude from the normal wall line. It is constructed directly on the rock and follows its natural form. It is one of the most extensive ancient constructions of the Helladic area. Building materials from other nearby building, including ancient temples, like the temple of Poseidon in Isthmia or the temple of Hera in Perachora were used for its construction. 153 small towers constructed in total.
In 1415, the Emperor Manuel Paleologos supervised the construction operations. The Ottomans destroyed the wall in 1423 and once again in 1431. Despot Constantine Paleologos repaired it three years later, but the Turks attacked again in 1446 and in 1452. After the domination if the Ottoman Empire, in 1460, the wall was completely abandoned.
Its modern form is a typical characteristic of the building style of Justinian’s era. In the joints ancient building material, mad bricks and stones and strong mortar were used. It mostly used the emplekton masonry which means transversely mounted blocks which prevent the collapse and make it difficult for removal of material from the body of the wall. Today, the wall has 67 towers and the small fortress of Isthmia attached to it.