The Forum (Agora) of Philippopolis was the commercial, administrative, and religious center of the ancient city. It hosted assemblies, debates, celebrations, and state affairs. In the vast area of the Forum (Agora), statues of emperors, their wives, and other notable figures with contributions to the city once stood tall. Shrines dedicated to revered deities were also erected here, along with inscriptions in their honor. Near the northern part of the area (area) stood the Temple of the Emperor, and next to it – a tribune, from where political leaders delivered their speeches. For centuries, the original layout of the Forum (Agora) remained unchanged. It was divided into two sections – a southern commercial area and a northern area, where a complex of public buildings was constructed. The open square space (area) was surrounded by porticos and shops on the eastern, southern, and western sides. The two main streets, cardo maximus and decumanus maximus, intersected in front of the eastern entrance to the square. In the stratigraphy of the Forum (Agora), four main construction phases have been identified, dating from the 1st to the 4th century AD.
On the northern side of the forum complex were located the public buildings used for city administration and other aspects of urban life. The Building of the Treasury has been epigraphically documented. In the northeastern corner, the Odeon (Bouleuterion) was discovered, and to its west – the City Library. In the northern part of the complex, inscriptions related to the religious and administrative life of the city have been found, as well as part of a public notice announcing gladiator games. Within the area, bases for statues and an exedra – a tribune for public speeches – were also uncovered.
Even today, the central city square of Plovdiv remains the heart of the city – just as the Forum was in the era of Antiquity.