In the spring of 1453 over 100,000 Turkish troops laid siege to Constantinople, and on 28 May the Sultan Mehmed II, afterwards referred to as 'Mehmed the Conqueror', finally captured the city.

He had hired a Hungarian gunmaker who built him a cannon that sent a ball flying a full mile.

In 1453, the sultan fired that gun, nicknamed Mahometta, at the Byzantine capital's ramparts and kept firing. Like so many of these giants, this cannon cracked after the second day and became unusable after a week. But Mehmet had other big guns. After 54 days of pounding, the 1,000-year- old Byzantine Empire, a victim of technological advance, finally fell.

Traditionally the fall of Constantinople has been seen as a catastrophe for Christianity and many contemporary church leaders were horrified by the news. The renowned humanist scholar Aeneas Silvius Piccolomini (later Pope Pius II) wrote to Pope Nicholas V:

But what is that terrible news recently reported about Constantinople? ... Who can doubt that the Turks will vent their wrath upon the churches of God? I grieve that the world's most famous temple, Hagia Sophia, will be destroyed or defiled. I grieve that countless basilicas of the saints, marvels of architecture, will fall in ruins or be subjected to the defilements of Mohammed. What can I say about the books without number there which are not yet known in Italy? Alas, how many names of great men will now perish? This will be a second death to Homer and a second destruction of Plato.'

As the capital of the Byzantine Empire, Constantinople was one of the last connections between the world of classical Rome and 15th-century Italy. It acted as a conduit for the recovery of much of the learning of classical culture. Piccolomini saw the city's fall as a repeat of the fall of the Roman Empire itself, its culture, learning, and architecture destroyed by the 'barbarian' 

Many European powers saw Mehmed's rise to power as an opportunity rather than a catastrophe. Within months of the fall of Constantinople both Venice and Genoa sent envoys to successfully renew trading relations with the city and the vastly enlarged Ottoman territories. By spring 1454 Venice had signed a peace treaty with Mehmed allowing it preferable commercial privileges. The Venetian Doge insisted 'it is our intention to live in peace and friendship with the Turkish emperor'. The resumption of amicable commercial relations was also matched by cultural and artistic transactions. In 1461 Sigismondo Malatesta, the feared Lord of Rimini, sent his court artist Matteo de' Pasti to Istanbul 'to paint and sculpt' the sultan, in the hope of formalizing a military alliance with the Ottomans against Venice. The Italian architects Filarete and Michelozzo were also both wooed by Mehmed as possible designers for his ambitious new palace, the Topkapi Saray, which, according to one 16th-century Venetian ambassador, 'everyone acknowledges to be the most beautiful, the most convenient, and most miraculous in the world'.

Rather than destroying the classical texts of the ancient world, Mehmed's library, much of which still remains in the Topkapi Saray in Istanbul, reveals that he coveted such books as zealously as his Italian counterparts.