http://agathe.gr/guide/odeion_of_agrippa.html
Odeion of Agrippa Late in the 1st century B.C. the Athenians were given money for a new marketplace by Caesar and Augustus, and the northern half of the old Agora square was filled with two new structures, ... Odeion of Agrippa Late in the 1st century B.C. the Athenians were given money for a new marketplace by Caesar and Augustus, and the northern half of the old Agora square was filled with two new structures, the Odeion of Agrippa and the Temple of Ares. ... It was a huge two-storeyed structure that must have dominated the square (Fig. 52). The auditorium, with its raised stage and marble-paved orchestra, seated about 1,000 spectators. ... It was rebuilt in the early 5th century A.D. as part of a sprawling complex, perhaps a palace, with numerous rooms, a bath, and several courtyards, which extended southward all the way across the old South Square (Fig. 55).