Several components of the fortification system of Stymphalos have been investigated over the project’s lifespan, the details of which are condensed in this section in order to present a brief overview of the components.
The circuit possesses seven known gates, some more researched than others. The largest gate of ancient Stymphalos, the Phlious Gate, was uncovered in 1926 by Anastosios Orlandos and re-excavated by the Canadian team in 2000. The overall objectives of this project were to take advantage of relatively dry conditions and prepare a more complete plan and obtain dating evidence for the gate’s installation. Work revealed that there had originally been a simple overlap gate similar to four others in the city walls, but it had been remodeled as part of a general updating of the city’s fortifications at the end of the 4th century BCE. Part of an earlier semicircular tower is visible in the foundation of the new gatehouse which featured a round central court opening to the east. The threshold for the gate itself was found on the west side of the court. Two rooms abut the gate’s northern side and may have served as guard rooms.
The Pheneos Gate was initially investigated by Anastasios Orlandos in 1927, although few details were published. New excavation revealed a number of interesting features, although its overall condition seems to have deteriorated since the 1920s. It is the least defended gateway known at Stymphalos, with an opening of 4.5 m, and was presumably guarded by the partly circular tower located several metres to the north where the city wall descends from the acropolis. A curious anta was discovered with the remains of two limestone benches running along the thickness of the city wall.
Finally there is the southwestern gate, a feature which has been somewhat enigmatic. Here a section of wall appears 2.6 m in front of the original line of the western city wall and its small, rectangular towers. The construction somewhat resembles the overlap style of other gates at Symphalos, but there is no evidence for an opening of any kind. The wall section could represent some kind of repair work, or the new wall could also have been the outer face of a redoubt, deliberately broadened to take a battery of catapults to cover the ground in this general area.
Two towers of note have also been subject to excavations. The acropolis artillery tower is a large (21.5 x 11 m) construction which dominates the highest point of the acropolis. It was initially much smaller and was expanded around 300 BCE with the construction of a massive stone wall and mud-brick linings three meters thick on the west and south. This expansion was likely carried out to support the weight and recoil of new catapult batteries. Its interior had been divided by rubble and mud-brick walls into a number of small rooms, one of which had the start of a staircase. Much later in its history the tower was reused as a Christian cemetery.
The site’s western artillery tower was added to the city wall on the site of an earlier simple rectangular tower but was later abandoned in the middle of the 2nd century BCE and later re-used as a burial place in the early Christian period. A notable find was a hoard of fourteen coins of the fourth century and early third century, indicating that the towers were constructed ca. 300 BCE.