On the evening of 21 Jan 1556, Humayun was walking in the terrace of his library at Sher Mandal in Delhi. While descending the steps, he heard the announcement for the evening prayer. He stood still upon the occasion and sat down on the second step till the proclamation was ended. When he was going to rise, he supported himself on a staff, which unfortunately slipped upon the marble, and he fell headlong from the top to the bottom of the stair. He was taken up insensible and laid upon his bed. He died on 24 Jan, at the age of fifty-one, after a reign of twenty-five years, in Kabul and India.
The History of Humayun: Humayun Nama was written by Gul-badan Begam, Humayun' s sister. Gul-Badan Begum (1523 - 1603), was daughter of Zaheruddin Muhammad Babur of India. She wrote Humayun nama at the behest of her nephew and at the emperor of India Jalal-ud-din Muhammad Akbar.
When Humayun was in exile Koh-i-noor Diamond was with