A cash-strapped emperor turned away the engineer whose cannon then destroyed his city

In 1452 the Hungarian gunfounder Orban offered Byzantine emperor Constantine XI a giant bronze cannon, but Constantinople couldn't pay him. Orban took the design to Sultan Mehmed II instead, and the resulting gun helped breach walls that had protected the city for over 1,000 years, ending the Byzantine Empire in 1453.

— Roger Crowley, Constantinople: The Last Great Siege, 1453 — Chapter 3, 2005
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