North of the octagonal church, and with the Hellenistic tomb-heroon continuing to function as nucleus, the spaces of prothesis, diakonikon, phiale and baptistery were developed. The later consisted of apodyterium, catechumena, baptistery and chrismarion. As a natural continuation, during the Christian period the heroon was transformed into a place of worship of an unknown martyr or even the Apostle Paul himself.
Further north, on the via Egnatia, the transition to the balneum (baths), first built during the Augustan age (31 BC - 14 AD), when the colony of Philippi was refounded, was provided via a stoa; the baths continued in operation until the 7th century AD. The north wing of the complex contained the porter's lodge, the oiling-room, the cold water reservoir with its tubs, and the latrines. At the center of the complex was a palaistra with an exercise area surrounded on three sides by a stoa. The eastern wing contained changing rooms and the cold bathing room (frigidarium); the southern wing was taken up by the medium-temperature room (tepidarium) and the hot room (caldarium) with its furnace (praefurnium). During the Early Christian era, the bath furnished the baptistery with hot water.
East of the baths, between two side streets, there rose atop an underlying Roman building an imposing secular complex with four wings of apartments surrounding a closed atrium. This complex has been identified as the bishop's residence. The southern and western wings of the edifice had upper stories with luxurious decoration which served as the residential and official reception rooms, probably in the form of a triclinium, while the rooms below had hearths, a fountain, wine-press, and large storage jars. The one-story eastern wing contained storerooms and workshops, and in the northern wing there were places for the personnel to live and work arranged around a small courtyard.
In the Octagon complex, some spaces were found to have continued in life and use immediately after its destruction by earthquake in the early 7th century.