The walls of Thessaloníki: a monument of Late Antique and Byzantine fortification

The fortifications of Thessaloníki constitute one of the best-preserved monuments of Early Christian and Byzantine military architecture. They mirror the city’s history, as they are the product of a long building process and continuous maintenance that dates from the foundation of the city by Cassander (316 BC) to the last quarter of the nineteenth and the beginning of the twentieth century. Although the main building phases date from the third, fourth, and fifth centuries AD, the physical and literary evidence of repairs, additions, and alterations demonstrates that the city’s defence was a never-ending arduous practice that entailed rich investments on the part of Thessalonian society and its leaders. Remnants of these celebrated walls stand today integrated into the dense urban grid of the city. Extensive restoration works have been carried out over the past twenty years to preserve this important part of the city’s architectural heritage. However, due to their long history, construction phases are hard to  date and their study presents great challenges.

The earlier extensive fortification phase that has been clearly traced by the archaeological records dates from the third century. During this period, the devastating intrusions of the Goths in the Balkans instigated the construction of a hastily built wall with the extensive use of spoliated material from the deteriorating public and religious institutions of the ancient city. Following this work, the major phase of the city’s enclosure dates from the end of the fourth to the middle of the fifth century. This ambitious fortification project followed the path and utilized the remains of earlier defences. Strong rectangular towers supported the walls, while a series of triangular bastions strengthened the more vulnerable lower walls of the city. As in the third century, the construction of walls and towers utilized whole parts of the ancient city. The fading institutions of the city’s pagan past, such as temples, gymnasia, and theatres were demolished for materials to help the city defend itself. The western land walls of the city bear the striking visual evidence of this practice. The façades of curtain walls and towers were built in two vertical zones of different building material. The lower parts of the walls were constructed of marble spolia, mostly benches and architraves from the city’s stadium. In contrast, both in texture and in colour, their upper part was built almost entirely in brick articulated with a shallow cornice and two tiers of superimposed double brick arches. A variety of brickwork crosses embellish the triangular spaces between these arches.

Additional construction during the fifth and the seventh centuries refined Theodosius’s defensive system. Yet, from the eighth century onwards, the city’s walls did not undergo radical changes or alterations. Restoration projects continued to employ solutions drawn from the rich repertoire of late Roman fortifications. Although the details of these building campaigns are hard to identify, it can be generally admitted that they did not implement significant modifications or introduce novel defensive solutions. At the beginning of the tenth century, a triangular acropolis was added to the northern part of the city’s enclosure incorporating a separate late Roman enclosure. The project demonstrates the need for an independent enceinte attached to the city walls. The acropolis did not only serve as a last place of refuge from an outside attack; it also accommodated the governor and the authorities of Thessaloníki as a bastion against popular unrest. During the late Byzantine period, a strong citadel developed in the northernmost tip of the acropolis, exemplifying the necessity for additional protection. Appropriately, the citadel was extensively rebuilt by the Ottomans in the 1430s, to serve as their headquarters and became known as Yedikule/Heptapyrgion due to the seven towers that punctuate its enclosure. The demolition of the sea walls and parts of the western and eastern land walls between 1873 and 1911 signalled the expansion of the modern city beyond its original fortified limits.

Beyond their defensive role, the walls of Thessaloníki defined the lives of its inhabitants for centuries, as they were the sensitive boundaries of daily life. They separated urban from rural, inside from outside, the familiar from the unfamiliar, the healthy from the sick, and the friendly from the hostile. Furthermore, these massive constructions physically engaged the citizens and visitors of Thessaloníki. The wall façades of towers and gates spoke a visual language that conveyed a broad spectrum of information. This mixture of different visual details produces a collage that bears signs of the long, layered utilitarian history of the city’s defences. Their façades present a monumental synthesis of building phases, techniques, and construction materials, embellished with spolia, inscriptions, and brickwork features. The iconography and the aesthetics of fortification façades were an important component of the visual culture of Thessalonian society, as they disseminated information and manifested civic identity.