Humayun sought the help of the Persian king Shah Tahmasp to reconquer his Indian legacy.
Explanation: Humayun was defeated by Sher Shah Suri in the battle of Chausa and then in the battle of Kannauj. After a heavy defeat, he had to leave India and seek refuge in Persia. The Persian king Shah Tahmasp helped Humayun to conquer Kabul and Kandhar. He also helped him in recapturing Delhi and Agra.