It was on this occasion, according to Theo Metcalfe, that Nader Shah discovered from the great courtesan Nur Bai that Muhammad Shah had hidden the Koh-i-Noor in his turban, and Nader won it by offering to swap turbans, ‘as brother rulers’, and as a lasting memento of their friendship. It was then, according to Theo, that the great diamond gained its name – the Koh-i-Noor or Mountain of Light – as Nader held the stone in his hand, awestruck.
