Philippi was a flourishing city in eastern Macedonia during the Hellenistic, Roman, and Early Christian periods, with continuous habitation from the mid-4th century BC to the 14th century AD. The city's 3500-meter long fortification wall was repaired and supplemented during the Roman and Byzantine periods.
The start of the Christian period at Philippi was marked by the arrival of the Apostle Paul in 49-50 AD and the founding of the first Christian community on European soil. The activities of Paul and his companions, Silas, Timotheus (Timothy), and probably Loukas (Luke), their imprisonment and their miraculous liberation are described in the Acts of the Apostles. Tradition holds that the first Christian convert, the dealer in purple Lydia, was baptized in the waters of the Gangitis, outside the modern village named in her honor. As may also be seen in his letter to the Philippians, the Apostle Paul developed special bonds with the city, which he visited on two further occasions, in 56 and 57 AD. However, there are no building remains of the 1st century AD at the archaeological site of Philippi. As time passed, the new religion displaced Roman syncretism, and the Greek language, which was used in preaching Christianity until the 3rd century AD, prevailed over Latin.
With the recognition of Christianity as the official religion of the empire (313 AD), Philippi became a metropolitan see (bishopric). During the following centuries, the city was adorned with monumental Christian churches (the Octagon, Basilicas A, B, and I, cemetery basilicas outside the walls) and transformed into a center of Christian worship.
However, from the 4th century AD, when there were successive invasions of the territories of the Byzantine Empire, such raids put a strain on the flourishing city. In 473, by virtue of a raid by the Goths, its suburbs were devastated. In the late 6th and early 7th centuries, earthquakes caused extensive damage to public and private buildings; some of these were repaired, while others were abandoned. At the same time, Arab-Slav raids influenced the urban character of the city and brought about the contraction, though not complete disappearance of social and economic life. Building remains that demonstrate the continuation of life at Philippi during the Middle Byzantine Period are found in Basilica I, in the Octagon, and in building blocks east of the Octagon.