Larisa is the ancient and medieval acropolis of Argos, located on a high rocky hill, within the town's boundaries to the west. The summit is occupied by the ruins of a Byzantine-Venetian castle. The site was fortified and in continuous use for nineteen centuries.
Traces of the Mycenaean fortifications (13th century BC) have survived in the castle's citadel, and some of the bulky, monolithic architectural elements were reused in later medieval defences.
Although the site was in continuous use from prehistoric times until WWII, it took the form we see today in the Middle Ages. The ancient walls, sections of which can still be seen incorporated into later masonry, were the main guide used when laying out the medieval fortifications. The fort is made up of the citadel at the top and a curtain wall. The walls are re-enforced by towers, which, as a rule, are triangular or quadrilateral. Later, from the 15th century, with the arrival of guns, the castle underwent extensive building work and was re-enforced with cylindrical towers.
The headquarters and military installations were most likely inside the citadel. A first millennium church has been found there. In 1174, a smaller church, dedicated to the Virgin, was built on the same site. The area inside the curtain slowly became residential, but this has yet to be explored. There were large cisterns in both the castle's enclosures. It kept this form until the end of the 14th century, with a few Byzantine and Frankish re-enforcements and alterations, and made Larissa one of the four most powerful castles in the Peloponnese, according to the Chronicle of Morea.
During the 15th century, there was extensive re-enforcement of the fortifications as the result of the castle constantly changing hands between the Venetians and the Ottomans, as well as the developments in defensive architecture brought about by the arrival of guns. Amongst these interventions was the construction of the partition that cut off the south section of the exterior precinct. The external defences were strengthened with large cylindrical towers which had gun loops. The citadel wall was made higher and re-enforced with triangular and quadrilateral towers and one oval one. At the same time, the Byzantine gate was blocked off and another was built a little further to the west. Some point after the mid-15th century, the now-ruined cylindrical central tower was built in the southwest corner of the citadel.
During the 16th century, the section of the exterior precinct south of the partition was abandoned, while another partition was added to the south of the citadel gate, creating an interior courtyard. On the eastern edge of the partition, a passageway was constructed with double gates.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.