The Odeon of Agrippa, located in the southern part of the Ancient Agora, was built at the end of the 1st century BCE as part of the extensive building program for the beautification of the city of Athens and the enhancement of its role as a cultural centre. Ancient sources attribute its sponsorship to Marcus Vipsanius Agrippa, son-in-law of Augustus. The construction of the building began around 16-14 BCE and was completed in 12 BCE, predating the death of its benefactor.

The Agrippeion, as it is alternatively known, was a large, luxurious building, originally intended for musical events. It had two stories and an estimated capacity of 1.000 people. The main hall, flanked on three sides by two-storey stoas, housed the semi-circular orchestra, an amphitheatre with 19 rows of seats and a stage decorated with sculptures. The upper floor had no internal columns – a daring architectural feature for the time – and a pitched roof that rested only on the walls. Externally, it featured columns and piers with Corinthian capitals. It had two entrances, one on the north side facing the square of the Agora and one on the south, through which the spectators entered the cavea, reaching the upper seats. The construction materials used for the building included limestone and marble sourced from Penteli, Ymittos, and Karystos.

Around the middle of the 2nd century CE, the roof of the Odeon collapsed. In order to improve its stability, internal modifications were made, resulting in the formation of two distinct spaces. The northern space incorporated the stage and part of the seats and was transformed into a theatre with a capacity of about 500 people. The northern entrance was also remodelled with the construction of a monumental pediment on the northern facade, the piers of which were decorated with carved colossal figures of Giants and Tritons. Apart from its architectural remodelling, it appears that the function of the building also changed, as it was now used as a hall for philosophical lectures. This shift of use is attributed, in part, to the construction of the Odeon of Herodes Atticus in 160 CE, designed to host artistic events for an audience of 6.000 spectators.

The Odeon of Agrippa burned during the raid of the Heruli in 267 CE. Shortly afterwards, some of its parts were used for the construction of the Late Roman wall of the city. Around 400 CE, a building complex was erected in the Agora – known as the Palace of the Giants – covering the Odeon and utilising colossal figures of the Giants and Tritons from the second phase of the Odeon for its monumental entrance.