Major problems (left behind by Babur) were −
The administration systems of Mughal Empire were weak and the finances were unjustifiable.
The Afghans had not been subdued entirely; hence, they were cultivating the hope of expelling the Mughals from India.
When Humayun ascended the throne at Agra, the Mughal Empire included Kabul and Qandhar; however, there was loose control over Badakhshan (beyond the Hindukush Mountains).
Kabul and Qandhar were under the charge of Kamran, Humayun's younger brother. Kamran was not satisfied with these poverty-stricken areas therefore, he marched towards Lahore and Multan, and occupied them.
Humayun, who was busy elsewhere, reluctantly accepted his brother’s autocratic act, as he was not interested in starting a civil war. However, Kamran accepted the suzerainty of Humayun, and promised to help him whenever it required.
The swiftly growing powers of Afghans in the east and Bahadur Shah (ruler of Gujarat) in the west were becoming problems that Humayun had to suppress.
The Afghans had conquered Bihar and overrun Jaunpur in eastern Uttar Pradesh, but in 1532, Humayun had defeated the Afghan forces.
After defeating the Afghans, Humayun besieged Chunar (from the Afghan ruler Sher Shah Suri).
Chunar was the powerful fort that commanded the land and the river route resting between Agra and the east; Chunar was popular as the gateway of eastern India.
After losing Chunar fort, Sher Shah Suri (also known as Sher Khan) persuaded Humayun to get permission to retain possession of the fort and he promised to be loyal to the Mughals. Sher Shah also sent one of his sons to Humayun court as a hostage. Humayun was in haste to return back to Agra; therefore, he accepted Sher Shah’s offer.
Bahadur Shah of Gujarat who was of the same age of Humayun had strengthened himself enough to threaten him (Humayun) in the north.
Ascending the throne in 1526, Bahadur Shah had overrun and conquered Malwa and then moved towards Rajasthan and besieged Chittor and soon abridged the Rajput defenders to sore straits.
According to some legends, Rani Karnavati (the widow of Rana Sanga), sent a rakhi (a thread that normally sister gives her brother and in return brother promises to protect her) to Humayun seeking his help and Humayun courteously responded.
Because of the fear of Mughal intervention, Bahadur Shah made an agreement with the Rana Sanga and left the fort in his (Rana Sanga’s) hands; however, he (Bahadur Shah) extracted a large indemnity in cash and kind.
Humayun spent one and half years of his time in building a new city nearby Delhi, and he named it as Dinpanah.
The buildings of Dinpanah were built to impress friends and foes alike. Another intention was, Dinpanah could also serve as a second capital, in case, Agra was threatened by the Gujarat ruler Bahadur Shah (who already had conquered Ajmer and overrun eastern Rajasthan.
Bahadur Shah invested Chittoor and simultaneously, he supplied arms and men to Tatar Khan (Tatar Khan was a cousin of Ibrahim Lodi), to invade Agra with a force of 40,000 men.
Humayun easily defeated Tatar Khan. The Afghan forces run away, as the Mughal forces arrived. Tatar Khan was defeated, and he was killed.
After defeating Tatar Khan, Humayun now invaded Malwa. He advanced forward slowly and cautiously, and covered a position midway between Chittoor and Mandu. Likewise, Humayun cut off Bahadur Shah from Malwa.
Bahadur Shah swiftly compelled Chittoor to surrender. It became possible because Bahadur Shah had fine artillery, which was commanded by Rumi Khan, an Ottoman master gunner.
Bahadur Shah did not dare to fight with the Mughals and he left his fortified camp and escaped to Mandu to Champaner, then to Ahmadabad and finally to Kathiawar. Thus the rich provinces of Malwa and Gujarat, as well as the huge treasure boarded by the Gujarat rulers at Mandu and Champaner, came into the hands of Humayun.
The fear of Bahadur Shah’s attack (on Mughal Empire) was gone with his death, as he died while fighting with the Portuguese.
Humayun’s absence from Agra (between February 1535 and February 1537), gave an opportunity to Sher Shah to strengthened his power and position.
Though superficially, Sher Khan continued to acknowledge loyalty to the Mughals, but steadily he planned to expel the Mughals from India.
Sher Khan was in close touch with Bahadur Shah, as he (Bahadur Shah) had helped him with heavy subsidies, which enabled him to recruit and maintain a large and competent army including 1,200 elephants.
After equipping a new army, Humayun attacked Sher Khan and captured Chunar and then he invaded Bengal for the second time, and seized Gaur (the capital of Bengal).
After the victory of Gaur, Sher Khan sent a proposal to Humayun that he would surrender Bihar and pay an annual tribute of ten lakhs of dinars if he was allowed to retain Bengal. However, Humayun was not in a mood to leave Bengal to Sher Khan.
Bengal was the land of gold, rich in manufactures, and a center for foreign trade. Secondly, the ruler of Bengal who had reached Humayun's camp in a wounded condition, informed that resistance to Sher Khan was still continued.
By observing underneath suspicious intention of Sher Shah, Humayun rejected Sher Khan's proposal and decided a campaign to Bengal. Soon after, the Bengal ruler submitted to his wounds; therefore, Humayun had to undertake the Bengal campaign all alone.
Bengal campaign of Humayun was not much beneficial, but rather was the prelude to the disaster, which overtook his army at Chausa after a year.
Sher Shah had left Bengal and went south Bihar. With a master plan, he let Humayun campaign Bengal so that he might disrupt Humayun's communications with Agra and bottle him up in Bengal.
Arriving at Gaur, Humayun swiftly took steps to establish law and order. But this did not solve any of his problems. On the other hand, Humayun’s situation was further made worse by his younger brother, Handal, as he attempted to crown himself of Agra. However, because of Sher Khan's master plans, Humayun was totally cut off from all news and supplies from Agra.
