Who commissioned the construction of Humayun's Tomb in Delhi in 1558?

Humayun's Tomb in Delhi was commissioned by his chief empress consort, Empress Bega Begum (also popularly known as Haji Begum), in 1558 following his death. Designed by the Persian architect Mirak Mirza Ghiyas, it was the first distinct grand garden-tomb structure built on the Indian subcontinent.