The story of Humayun and Rani Karnavati is part of the Raksha Bandhan legends. Of the various Raksha Bandhan legends, the legend of Humayun forms an important link.
Rakhi Festival : Rakhi Legends : Humayun and Rakhi
Humayun and Rakhi
During the medieval period, we come across a new dimension of Raksha
        Bandhan, when the Mughal emperor Humayun received Rakhi from Rani
        Karnavati of Chittor. In 16th century the sultan of Gujarat attacked the
        kingdom of Chittor. To save her kingdom from the invader, Rani Karnavati
        sought help from the Mughal emperor Humayun and sent the sacred thread
        (Rakhi) for him. Humayun is said to been touched by the bond and marched
        to protect the kingdom of Chittor. Though Humayun marched towards
        chittor to help the distressed Rani but he could not reach at the right
        time and the Rani, along with other Rajput ladies committed Jauhar to
        save their honor.
		

