The present tower dates from the reign of the Ottoman Sultan Suleiman the Magnificent (1520-66). There was an older tower on the same site, probably built by French knights during the period of the Latin Empire in Constantinople. The Tower was used by the Ottomans successively as a fort, garrison and a prison. In 1826, at the order of the Sultan Mahmud II, there was a massacre of the prisoners in the Tower, and it acquired the name "the Bloody Tower."
The Tower was for centuries part of the walls of the old city of Thessaloniki (known as Salonik in Ottoman times), but these were demolished in 1866. When Thessaloniki was captured by the Greeks during the Balkan War of 1912, the tower was whitewashed as a symbolic gesture of cleansing, and acquired its present name. King George I of Greece was assassinated at the White Tower in March 1913.
The Tower is now a buff colour but has retained the name White Tower. It now stands on Thessaloniki's waterfront boulevard, Nikis (Victory) Street. It houses a Byzantine museum and is one of the city's leading tourist attractions. The Tower is under the administation of the Ephorate of Byzantine Antiquities of the Greek Ministry of Culture.
After the independence of the Republic of Macedonia in 1991, the White Tower became a symbol of the dispute between Greece and the Republic of Macedonia over the name "Macedonia" and the symbols of Macedonian history (see also Vergina). Greek nationalists alleged that the Republic of Macedonia was using the White Tower on its coat of arms and its new banknotes, allegedly implying a territorial claim over Thessaloniki. In fact, the "banknotes" had been printed by a private company in the Republic of Macedonia, not by the government. The official coat of arms of the Republic of Macedonia has never included the White Tower.
It is true that Macedonian nationalist groups have advanced territorial claims over what they call "Aegean Macedonia," and that these groups use the White Tower as a symbol of their claims that Thessaloniki (which they call Solun) ought to be part of a greater Republic of Macedonia. Since the 1995 agreement between Greece and the Republic of Macedonia, however, it does not appear that the government of the Republic of Macedonia has given these groups official encouragement.