Thessaloniki is an enduring city, a city of youth with a long history and many attractions. For 23 centuries, from 315 BC when it was built by Kassandros to the present day, the city has experienced an unbroken urban life. Greeks were its founders and the Greek language and culture have been its timeless stamp. The city has experienced periods of prosperity and decline. Romans, Slavs, Turks and Franks left their indelible mark. In the last centuries (15th-20th century) Greeks, Jews and Turks were the main co-inhabitants of the multicultural and multireligious society. It was the second great city of three empires, Roman, Byzantine and Ottoman. In 1912, the city was incorporated into the Greek state and continues to play its historical and strategic role, hence its nickname of “co-capital”. Important representative monuments from all its historical periods have been preserved. The most glorious period of Thessaloniki is considered to be the Early Christian and Byzantine periods, which lasted for about a thousand years. Throughout the Byzantine Empire, Thessaloniki was second only to Constantinople in population, dynamism and prestige. From the monumental wealth of this period, several monuments have survived, giving Thessaloniki the nickname of Byzantine metropolis and “Symvasilevousa”.