Thessaloniki, the "Metropolis of Macedonia" according to Strabo, "the first after the first" or "co-royal " city of the Byzantine sources, "co-capital" of Greece in recent years, has already completed twenty-three centuries of continuous historical presence .It was founded in 316 BC by King of Macedonia Cassander, who inhabited twenty-six small towns and villages in the region, coastal and landlocked. The new city, built at the head of Thermaikos gulf, having in the south the sea, in the east-northeast the Mount Chortiati, in the north lower elevations and in the northwest- west a long and fertile plain, owned a privileged geographical position: it was naturally fortified, it had a safe harbor, which linked the interior of Macedonia with Aegean and the eastern Mediterranean, and it was among terrestrial roads leading in all directions. Thus, Thessaloniki became very soon - since the early-middle Hellenistic period - an important trading hub and a significant military-naval base. In subsequent seasons and throughout the centuries from ancient times until today the city - along with various historical factors and favorable geopolitics facts - has never ceased to grow, to be a metropolitan center and a crossroad between western and eastern world, to be a meeting and interaction place of different people, religions and cultures, playing a leading role in the political, military, administrative, financial, commercial, artistic and intellectual changes and activities.
In Roman times, Thessaloniki became the headquarter of a large department, the province of Macedonia (provincia Macedonia), which included, apart from Macedonia, Epirus, Illyria, and other territories that stretched from the Evros river to the south Adriatic coast . The city was the largest station of the Egnatia road (via Egnatia), the famous military road that started from Durres and ended in Evros, linking the western with the minor-Asia’s possessions of the Roman Empire. On the verge of the 3rd to the 4th century AD, Caesar Galerius, one of the four rulers of the vast Roman Empire and, more specifically, the commander of the Balkan peninsula, decided to settle in Thessaloniki, making it the capital of the province.
In 322-323 AD at the southwest edge of Thessaloniki there was constructed by Constantine the Great an artificial harbor, which undoubtedly contributed decisively to the progress and prosperity of the city. Meanwhile, the foundation of Constantinople was held and that was the actual start of the long Byzantine period. Throughout its presence, Thessaloniki was the second largest city of the Byzantine Empire and the most important urban center of its European part. Despite successive and repeated sieges (and sometimes conquests) that it experienced by various invaders (Goths, Avars, Slavs, Saracens, Bulgarians, Arabs, Catalans, Normans, Franks and Ottomans), despite the deep economic crisis, the hard dynastic quarrels, the serious social conflicts and the intense religious disputes, the Byzantine Thessaloniki managed to maintain its vitality and dynamics, its glory and its productivity. The external enemies and internal trials have never been able to stem the city's cultural creativity, which from the early Christian to the late Byzantine years remained at extremely high levels.
On March 29th , 1430 Thessaloniki was definitively captured by the Turks and a new, major chapter opened in its history. In nearly 480 years of bondage and occupation that followed, the city acquired the character of an Islamic center of the Ottoman Empire, nevertheless without losing its urban character. In an era that previous thriving Byzantine cities were converted, after their occupation by the Turkish, into peaky towns, the inhabitants of Thessaloniki - despite demographic shocks that occurred over time - gradually increased. The gradual rise in population was accompanied by a radical and massive change in the ethnic-religious composition of the city: in Thessaloniki, unsurprisingly, were settled numerous Muslims, as well as thousands of Jewish refugees who arrived mainly from the Iberian and southern Italian peninsula. In the cosmopolitan and multicultural environment that shaped in the city since the 15th century ,the Greek Orthodox community, although it was threatened and had received strong blows several times, it was not degenerated, nor it was split dangerously, staying not only alive but also thriving.
With the liberation of Thessaloniki by the Turks on October 26th 1912 the modern period of the city’s long history was inaugurated. During the 20th century, Thessaloniki passed from old to new, experiencing host of changes in many and diverse sectors and levels, however, it remained a populous and bustling city with a distinct color and a specific identity. At the early dawn of the 21st century, the Macedonians’ capital corresponding and adapting to situations and circumstances that vary continuously, is moving forward with its past being evident thanks to the several monuments that have survived scattered within the existing urban fabric: Hellenistic and Roman antiquities, Byzantine churches with mosaics and murals, impressive architectural elements like walls, towers and castles, Ottoman mosques and baths, emerge among high buildings, representing timeless varied cultures and making the city of Thessaloniki a singular and unique "open" museum of art.