BYZANTINE BUNGLE

The fall of Constantinople was a really big thing. It marked the end of the Middle Ages and the start of Ottoman domination in south-eastern Europe. But when the Ottomans began to attack in 1453, the city was not fazed.

Its defences and high, thick walls were famous for keeping out trouble.

However, all was lost thanks to human error. Historian Doukas said careless soldiers forgot to shut a small gate. A crowd of Ottomans swiftly gained entry and raised their banner.