The siege of Thessalonica between 1422 and 1430 was an ultimately successful attempt by the Ottoman Empire under Murad II to take the Byzantine city of Thessalonica. Initially, the Sultan desired to capture the city in order to punish the ruling Byzantine Palaiologoi dynasty for their attempts at inciting rebellion within the Ottoman ranks. Toward this end, Murad II laid siege to the harbor of Thessalonica in 1422. In 1423, the Byzantine despot Andronikos Palaiologos handed the city to the Republic of Venice, which assumed the burden of its defence (the rumour that it was sold is baseless).
The Ottomans maintained their naval blockade until 1430, when they assaulted and took the city. The Venetians had not realized how expensive the defense of the city was. Nonetheless, it held out despite severe hunger within the city. Murad II had been engaged in numerous battles with the Venetians, Karamanids and numerous pretenders; when all had been subdued, a large army was sent to Macedonia and the city was subjected to three days of pillage and destruction after its capture in 1430. At that time population numbers were modest.
Mango, Cyril, The Oxford History of Byzantium. 1st ed. New York: Oxford UP, 2002. See also John R. Melville-Jones, 'Venice and Thessalonica 1423–1430. The Venetian Documents', (Padua 2002) and 'Venice and Thessalonica 1423–1430. The Greek Accounts' (Padua 2006).
^John Julius Norwich, Byzantine: The Decline and Fall (Alfred A. Knopf Pub.: New York, 1998) p. 394
^John Julius Norwich, A History of Venice (Alfred A. Knopf Pub.: New York, 1982) p. 343
^Mango, Cyril. The Oxford History of Byzantium. 1st ed. New York: Oxford UP, 2002. pg 277
^Lord Kinross, The Ottoman Centuries: The Rise and Fall of the Turkish Empire, p. 85
^According to Cyril Mango, the number was as low as 2,000 people (Mango 2002, p. 277). On the other hand, the New Cambridge Medieval History, Vol. 7 (1998), reports that 7,000 Thessalonicans were taken captive (p. 778).