number of Christian churches that were built. Significantly however, these churches were built within a restricted area of the town, sheltered by the walls of the acropolis. This has been taken as evidence that the large fortified perimeter of the ancient town was no longer defendable, and that the population of the city had considerably diminished. Nevertheless, the number, size and quality of the churches constructed between the 5th and 6th centuries are impressive. Four basilicas adorned with rich mosaic floors and elaborate architectural sculptures (such as the ram-headed column capitals – see picture) have been excavated, as well as a church with a hexagonal central plan which evokes that of the basilica of St Vitalis in Ravenna. It is difficult to find reasons for such municipal extravagance in such a small town. One possible explanation provided by the historian André Boulanger is that an increasing ‘willingness’ on the part of the wealthy upper classes in the late Roman period to spend money on local gentrification projects (which he terms euergetism, from the Greek verb ; meaning 'I do good') was exploited by the local church to its advantage, which led to a mass gentrification of the urban centre and of the agricultural riches of the city's territory. Amphipolis was also a diocese under the metropolitan see of Thessalonica – the Bishop of Amphipolis is first mentioned in 533. The bishopric is today listed by the Catholic Church as a titular see. Final decline of the city The Slavic invasions of the late 6th century gradually encroached on the back-country Amphipolitan lifestyle and led to the decline of the town, during which period its inhabitants retreated to the area around the acropolis. The ramparts were maintained to a certain extent, thanks to materials plundered from the monuments of the lower city, and the large unused cisterns of the upper city were occupied by small houses and the workshops of artisans. Around the middle of the 7th century, a further reduction of the inhabited area of the city was followed by an increase in the fortification of the town, with the construction of a new rampart with pentagonal towers cutting through the middle of the remaining monuments. The acropolis, the Roman baths, and especially the episcopal basilica were crossed by this wall. The city was probably abandoned in the eighth century, as the last bishop was attested at the Second Council