In the ancient times, Agora happened to be the seat of political, commercial, administrative and social activity, the religious and cultural centre, and the seat of justice of Athens. It was only early in the 6th century, in the time of Solon, that Agora became a public area. During this time Peisistratus removed the other houses, closed wells, and made it the centre of Athenian government. He also built a drainage system, fountains and a temple to the Olympian gods. Cimon later improved the agora by constructing new buildings and planting trees. In the 5th century BC there were temples constructed to Hephaestus, Zeus and Apollo.
Buildings and structures of the classical agora included:
- Peristyle Court
- South Stoa I and South Stoa II
- Colonos Agoraios
- Agora stone
- Monument of the Eponymous Heroes
- Old Bouleuterion
- New Bouleuterion
- Temple of Hephaestus
- Temple of Apollo Patroos
- Stoa of Zeus
- Altar of the Twelve Gods
- Royal stoa
- Temple of Aphrodite Urania
- Stoa of Hermes
- Stoa Poikile
Many buildings were added later to this site. Those in place by the 2nd century included:
- The Middle stoa which sat across the sanctuary, in front of the Heliaea
- A small Roman temple was added in front of the Middle stoa.
- An Altar of Zeus Agoraios was added just to the east of the Monument to the Eponymous Heroes.
- The Temple of Ares, dedicated to Ares, the god of war, was added in the north half agora, just south of the Altar of the Twelve Gods.
- The Odeon of Agrippa and accompanying gymnasium were added in the centre of the agora.
- The substantial Stoa of Attalos was built along the eastern edge of the agora.
- A collection of buildings were added to the south-east corner: the East stoa, the Library of Pantainos, the Nymphaeum and a temple.