The Stoa of Eumenes is a stoa on the acropolis of Athens, sited between the Odeion of Herodes Atticus and the Theater of Dionysos. It was built against the slope of the hill (meaning it needed a retaining wall supported by piers and round arches. It is named after its builder, Eumenes II of Pergamum (whose brother Attalus II of Pergamum built the Stoa of Attalus in Athens's agora, probably commissioning it from the same architect). It was two-storied, 46m longer than the Stoa of Attalus and unlike it had no rooms behind its two-aisle hall, meaning it was designed for promenading rather than business. Originally marble-faced, its arcades were built into the 1060 Byzantine defensive wall and are still visible. It had Doric columns externally, Ionic columns on the ground-floor interior and Pergemene-type capitals on the top floor interior. In front of the Stoa are the foundations of the 320BC Monument of Nikias.