On the South Slope of the Acropolis, and between the Herodeon and the Theater of Dionysos, stretches the Grand Portico of the King of Pergamos Eumenes II (197-159 BC), known today as Stoa of Eumenes. Like his predecessor King Attalos, Eumenes II was a great friend and admirer of Athens. The Portico was an imposing two-floor building of some length, which provided the spectators of the Dionyssos Theater with a lobby during intermission and served as shelter from rain and sun. It also served as a weather-covered place for the Athenians to take a stroll.
The portico, having the length of an ancient stadion, about 163 m (534 ft) long and 16 m (56 ft) wide, consisted of a double colonnade, one along the outer side and forming the front, the other in the middle. The façade of the ground floor had an outer row of 64 Doric columns, while a row of 32 columns of the so-called Pergamene order with channels formed the interior colonnade. On the upper floor, the roof was supported by two rows of columns corresponding to those below, but differing in style. Through its west wing the ground floor of the stoa communicated with the lower section of the Dionyssos Theater, while the upper floor led directly through the upper part of the theater to the Peripatos. On the West side was a fountain, which communicated with a well of the terrace.
The Travlos plan of the Acropolis buildings.
Access to the colonnade was gained by means of three steps at the front. The hindmost wall, constructed of conglomerate stones and mounted on a socle clothed in bluish marble, was supported by arches, which served as buttresses to the supporting wall of the upper terrace; where the Circular Way of the Acropolis, the famous Peripatos passed through. Some foundations in conglomerated stones which are found near the stoa on the SE angle, are supposed to be the remains of the choragic monument of Nikias, constructed in 319.
In 1060, during the Byzantine period, the buildings on the southern slopes of the Acropolis were incorporated in the fortifications of the citadel, the Rizokastron. The defensive wall, coming from the Propylaea, took in the outer walls of the Herodeon, the arcades of the Stoa of Eumenes and the walls of the parodoi (side-streets) of the Theater of Dionysos.The Stoa of Eumenes was totally destroyed in the middle of the third century, perhaps with the Herulian incursion of 267 AD.
The Stoa of Eumenes, connecting the Herodeon (left) to the Theater of Dionyssos (right).