Khusrau (elder brother) was the potential contender of Shah Jahan; therefore, as long as he (Khusrau) was alive, he was a great hurdle (for Shah Jahan). In 1621, Shah Jahan killed Khusrau (who had been kept in his custody) and spread the news that he died due to colic (abdomen pain).
Shahriyar, a younger brother of Shah Jahan, married to Nur Jahan’s daughter (from her former husband) and taken an important command that mentally disturbed Shah Jahan; hence, he (Shah Jahan) rebelled.
The immediate cause of Shah Jahan’s rebel was the order that given to him to proceed Qandhar, which had been besieged by the Persians, but he refused.
Shah Jahan was afraid that the Qandhar campaign would be a long and difficult one and that might intrigue against him (i.e. during his absence from the court). Hence, he demanded full authority such as full command of the army, which included the veterans of the Deccan, complete control over Punjab, control over a number of important forts, etc.
Jahangir was enraged because of strange demands of Shah Jahan. Further, Jahangir had been also convinced that the prince was meditating rebellion; hence, he wrote harsh letters and took punitive steps, which only made the situation worse and resulted in an open breach.
From Mandu (where he was stationed), Shah Jahan moved to attack Agra in order to capture the treasures lodged there.
The Mughal commander, posted at Agra, was vigilant and he foiled Shah Jahan’s move. After failing at Agra, Shah Jahan moved to Delhi; by the time, Jahangir had assembled a large army under the command of Mahabat Khan.
Mahabat Khan was ordered to move on to Mandu (Malwa), Prince Parvez appointed the nominal commander of the army. Another army was sent to Gujarat.
Shah Jahan was forced out of the Mughal territories and compelled to take shelter nearby the Deccani rulers, his erstwhile enemies. Further, he crossed the Deccan into Orissa, controlled the governor by surprise, and then he also took the control of Bengal and Bihar.
Mahabat Khan was again deputed against Shah Jahan and he successfully forced Shah Jahan to retreat to the Deccan again. This time, Shah Jahan made an alliance with Malik Amber who was once again at war with the Mughals. But the by time, Shah Jahan failed to success in his expedition and hence he wrote a humble letter his father Jahangir.
Jahangir realized that time came to pardon and conciliate his brightest and most energetic son. However, in 1626, as part of the agreement, two of Shah Jahan's sons, namely Dara and Aurangzeb, were sent to the Jahangir’s court as a hostage, and II tract in the Deccan was assigned for Shah Jahan's expenses.
Jahangir’s health was gradually deteriorating, however, he was still mentally alert, and did allow to make any decisions without his consensus.
Jahangir's illness increased the vulnerability that an ambitious noble might try to use the situation to take supreme power in his hands.
Mahabat Khan who had played a leading role in controlling Shah Jahan's rebellion, had been feeling disgruntled because certain elements at the court were eager to clip his wings after the end of the prince's rebellion.
Mahabat Khan’s alliance with Prince Parvez was also a threat. Summoned by the court to render accounts, Mababat Khan came with a trusted body of Rajput and seized the emperor at an appropriate moment when the royal camp was crossing the river Jhelum on its way to Kabul. Nur Jahan, who had not been apprehended, escaped.
Nur Jahan played a trick and hence, she surrendered herself to Mahabat Khan in order to be close to Jahangir, and tried to pause the suspicions of Mahabat Khan; however, she was secretly trying her best to weaken his (Mahabat Khan) position.
Over a period of time, Nur Jahan took advantage of the mistakes and weakness of Mahabat Khan (who was actually a soldier, and not a diplomat or an administrator), she managed to wean away most of the nobles from Mahabat Khan's side. Further, Rajput soldiers were also not in support of Mahabat Khan.
Soon Mahabat Khan realized his precarious position, and hence, he fled from the Jahangir’s court. Later, he joined Shah Jahan.
Nur Jahan’s victory over Mahabat Khan was her greatest victory and a true reflection of her cool courage and sagacity. However, she could not enjoy her victory for long, as Jahangir died (in 1627).
After Jahangir’s death, Asaf Khan, supported by the divan, the chief nobles, and the army, arrested Nur Jahan and sent an urgent summons to Shah Jahan. In the meantime, Asaf Khan appointed Khusrau’s son as puppet emperor.
Shah Jahan’s younger brother, Shahriyar, made a feeble effort for the throne, but he was easily defeated and thrown into prison (and blinded).
Shah Jahan's reign effectively from 1628 to 1658), which was full of distinct activities (as discussed above).
