Philippi (Φίλιπποι) was a city of eastern Macedonia, in a rich plain astride the Via Egnatia, slightly inland from its port at Christoupolis. It was an important economic and cultural center in the 4th century.

At Philippi are preserved the remains of many buildings, especially from the 5th-6th century, and many tombs both Christian and pagan, with coins through Justinian I. Basilica A, which was built on a succession of levels rising from forecourt to nave, and Basilica G were decorated with marble and mosaic floors. Basilica B (6th century) was an enormous vaulted structure with a dome over the central bay; the dome collapsed before completion. The so-called Octagon was built by the bishop Porphyry (mid-4th century), rebuilt with a mosaic pavement in the late 4th or early 5th century, and inscribed in a square in the early 6th century. It was the cathedral of Philippi and part of a vast complex, including a bishop’s palace, which became the focus of civic life until a fire of the 7th century. Aaccording to Pelekanides, the cult of the apostle Paul that was centered in the Octagon continued a Hellenistic hero cult. Among the Christian monuments of Philippi is an inscription of the 5th century on the city gates containing fragments of correspondence between Christ and Abgar of Edessa.

The fate of Philippi after the 7th century is obscure. Slavs settled in much of the surrounding territory. Bulgarian invasions of c. 812 forced Greeks to flee from the fortress of Philippi. Two fragments of a Bulgarian inscription dated to the second quarter of the 9th century survived in Basilica B; one of them mentions the benefactions made to Christians and their ingratitude. Byzantine writers are silent about Philippi except for the author of the Vita Basilii who “remembered” Philippi as one of the Macedonian poleis at the time of Herakleios. It was a kastron around c .965, when Nikephoros II Phokas organized the repair of its rampart, an event recorded in an inscription. The remains of the walls show that additions to the ancient fortifications were made during the Byzantine period, including a proteichisma, or low external wall, two inner walls strengthening the lines of resistance,*; and a “donjon,” or medieval castle, as an independent fortified structure.

According to al-Idrisi, Philippi was a trade center in the 12th century. According to Kantakouzenos, it was an impregnable fortress protected by precipitous rocks and swamps. It is rarely mentioned in later sources, although we can assume that Philippi shared the fate of eastern Macedonia. In 1208 the Latin emperor of Constantinople, Henry of Hainault, defeated the Lombards, who had refused to let him into Christoupolis, “in the valley of Philippi.” In 1246 John III Vatatzes held a military council in Philippi. The city survived the attack of the Catalan Grand Company in the early 14th century but was later taken by Stefan Uroš IV Dušan. Gregoras describes an expedition of Matthew I Kantakouzenos against the asty of Philippi in 1355; the caesar Voihna, Serbian ruler of Drama, took him captive. The city probably fell to the Ottomans in 1387. The history of the ecclesiastical metropolis of Philippi is also obscure, and the data about it before the 10th century are questionable; only in the notitiae of the 10th-12th century is there evidence about it. It probably declined in rank during the Palaiologan period, and Christoupolis and Drama ceased to be its suffragans.