With the transfer of the seat of the Eastern Roman Empire to Constantinople (330 AD), the dominance of Christianity (4th c. AD), and the graduation Hellenizing of the Eastern Roman state, the Roman colony of Philippi regained its character as a Greek city. With the change of religion, the large public buildings, which had been destroyed by earthquakes or other causes, were succeeded by monumental Christian churches, and the city was transformed into a center of Christian worship. The most important monuments of this era, are:
The octagonal is an Early Christian octagonal temple on the eastern side of the Agora, which was excavated in the 1960s and brought to light two more ancient temples, a fact that created the name of the octagon complex. A baptistery and other findings, a public bath, an episcopal mansion and warehouses are being developed around the octagonal temple. In the center of the complex there is a large Macedonian tomb of the Hellenistic period.
In the temple was originally built in the middle of the 4th century. the Euktirios (good building) House of Porphyrios. Immediately on its ruins is built a three-aisled Basilica and in the 5th century the octagon (some building phases date back to the 6th century). According to an epigraphical testimony, the temple was dedicated to the Apostle Paul, a fact that shows, along with its location in the center of the city, beside the market and the presence of the Bishopric, that it was the Cathedral of the Philippisians. Among the findings of the temple are distinguished the intent, the diaconate, the baptistery (lighting and baptistery), the fountain and other common in the Early Christian basilicas. To the west, before the temple, there was a small three-aisled gallery that led to the nearby and north crossing Egnatia Street.
At the same time with the building of the Octagon and to the east of its prefectures, the independent building complex of the Episcope is built with an outdoor closed courtyard in its center. Around it there are square wards of apartments, of which the south and the west had a second floor, which used to house the bishop and the other clergy. The existence of an apartment, fireplaces, dunes, two bars for grape pressing, many and large warehouses, reception halls and gatherings testify to the well-organized church of Philippi and its interest in its distressed brothers. Moreover, the church of Philippi was the leader of works of devotion from the time of Apostle Paul, and the Church at the very least was pioneering in the actual expression of love and charity.
Between the Egnatia Street and the cult buildings of Octagon is one of the Philippi baths which was annexed to the complex of the metropolitan church of the city, supplying with its hot water its baptistery. The entrance of the valaneia was on the Egnatia road and its facade was adorned but at the same time it protected the bathers from the weather with a narrow gallery. To the right of the entrance there was the bath’s fund and right after the entrance a closed yard. All around were auxiliary apartments, like a toilet and a cold water tank with a sprinkler. In the background, there were three houses: the cold (frigidarium), the warmer (tepidarium), and the warmer in the middle (caldarium) near the praefurnium. Its foundation is believed to have taken place in the years of August (31 BC-14 AD).
SAINT PAUL’S PRISON
At the south-western corner of the patio, to the right of the monumental scale, there is a double water tank of Roman times. After the destruction of the Early Christian basilica A, this tank was transformed into a space of worship. Remains of a fresco with a representation of Christ sitting on a throne between two saints or angels are kept on the eastern wall. A chapel was established above the reservoir where the worship was removed from the ruined basilica. Chapters of the eastern and western walls are preserved from the chapel. According to the tradition, this tank is considered to be the “prison” of the apostle Paul.