The Square Peristyle is the modern name for a structure on the east side of the Ancient Agora of Athens, which was among the largest peristyles built in Classical Grece. Construction began around 300 BC, but was abandoned ca. 285-275 BC, leaving the structure unfinished. It probably served as Athens' law courts at the beginning of the Hellenistic period, but fell out of use. In the early second century BC the building was demolished and the material was reused in South Stoa II, on the southern side of the Agora. The Stoa of Attalos was subsequently built over the top of its foundations.
Traces of the structure were revealed by American excavations in the 1950s, but were covered over shortly thereafter when the Stoa of Attalos was rebuilt.
Description
The structure stood on the east side of the Agora, next to the Panathenaic Way and would have dominated the space in the early Hellenistic period. The north side is aligned with an east–west cross-road, the southwest corner touched the Panathenaic Way. It was a square building with sides of 58.56 metres in length, surrounding a central courtyard, which was lined with columns in the Doric order. It was the largest of at least seven stoas built in Athens in the late fourth and early third centuries BC, and the second-largest peristyle attempted in Greece up to that time, after the Anactorium at Vergina. The use of a peristyle design may have been inspired by the nearby Pompeion, but there was no close model for the design. Some aspects of the colonnade and entablature are modelled on the Stoa Poikile, the Stoa of Zeus, and the Propylaea.
The building was never completed. The north wing was certainly finished, while on the south side the foundations were not even laid. A large entranceway on the west side and a small one on the east were planned, but never built - the spaces were simply left open. At least the northern parts of the western and eastern wings were finished, but probably not for their full length. Many blocks still have rough surfaces, which were to protect them during transport and then be chiselled off once they were in situ.
The structure was built using a basic unit of 0.32 metres - shorter than the normal unit for Classical Athenian buildings, which was 0.326-0.327 metres. The outer walls were made out of mudbrick, probably because it was cheap. The internal colonnade and entablature was made out of limestone from the Kara quarry at the foothills of Mount Hymettus. This stone resembled marble, but was easier to work and Kara was closer to the city than the marble quarries.
Outer walls
The north wall was one of the best-preserved sections, since it acts as a retaining wall and was thus incorporated into the stoa of Attalos and the Post-Herulian Wall. It survives to a height of nine courses. The lower courses were set in the bedrock and made of soft, creamy poros which was meant to be covered over by soil so that it was not visible. The upper section has made from hard grey poros. Remnants of the mudbrick wall of the superstructure were found, fallen to the south. Much of the wall was relocated to form the back wall of South Stoa II, where it is most easily visible.
The north and south ends of the west wall are attested. In the north part of the wall, two courses of soft, white poros were preserved, many of them repurposed from a predecessor structure, Building A. The south part of the wall is made of brick-red conglomerate blocks, preserved in only a single course. The middle 17 metres of the west wall are totally missing and it appears that no foundations were ever laid. It was probably intended that there would be a monumental entrance gate here, but it was never built. A monument base was erected in the Agora in front of the west wall.
The foundation trench for the east wall is preserved for almost its entire length, but almost all of the stone blocks, which were brick-red conglomerate, have been repurposed. There is a 2.25-metre gap at the middle of the wall. This was probably intended for a smaller secondary entrance gate, but it was apparently also left unfinished. The bedrock has been worn down by heavy traffic. There are traces of a cobblestone road leading away to the east.
The foundation trench for the south wall was roughly dug, but then allowed to fill up with dirt by 275 BC; no stones were ever laid. A row of shops was subsequently erected on the area where this wall should have stood.