Nasir ud-din Muhammad Humayun (full title: Al-Sultan al-'Azam wal Khaqan al-Mukarram, Jam-i-Sultanat-i-haqiqi wa Majazi, Sayyid al-Salatin, Abu'l Muzaffar Nasir ud-din Muhammad Humayun Padshah Ghazi, Zillu'llah) (17 March 1508– 4 March 1556) (OS 7 March 1508-OS 22 February 1556) is the second Mughal Emperor who rules present day Afghanistan, Pakistan, and parts of northern India from 1530–1540 and again from 1555–1556.

Like his father, Babur, he loses his kingdom early, but with Persian aid, he eventually regains an even larger one.

On the eve of his death in 1556, the Mughal empire spans almost one million square kilometers.

He succeeds his father in India in 1530, while his half-brother Kamran Mirza, who is to become a bitter rival, obtains the sovereignty of Kabul and Lahore, the more northern parts of their father's empire.

He originally ascends the throne at the age of 22 and is somewhat inexperienced when he came to power.

Humayun loses his Indian territories to the Pashtun noble, Sher Shah Suri, and, with Persian aid, regains them fifteen years later.

Humayun's return from Persia, accompanied by a large retinue of Persian noblemen, signals an important change in Mughal court culture, as the Central Asian origins of the dynasty are largely overshadowed by the influences of Persian art, architecture, language and literature.

Subsequently, in a very short time, Humayun is able to expand the Empire further, leaving a substantial legacy for his son, Akbar.