Jai Singh I (15 July 1611 – 28 August 1667) was a senior general ("Mirza Raja") of the Mughal Empire and the Raja of the Kingdom of Amber (later called Jaipur). His predecessor was his grand uncle, Mirza Raja Bhau Singh.
Accession and early career
At the age of 10, Jai Singh I became the Raja of Amber and the head of the Kachwaha Rajputs. His military career spans the full reign of Shah Jahan and the first decade of Aurangzeb's reign. Jai Singh's military career began during the accession of Shah Jahan as the Mughal emperor in 1627. Taking advantage of the change in sovereigns, Jai Singh's commander in the Deccan, Khan Jahan Lodi, rebelled with his Afghan followers. However, Jai Singh brought away his own army to the north and then joined the campaign to defeat the rebels. Jai Singh was made a commander of 4000 for his service.
In 1636 Shah Jahan organized a grand campaign against the Deccan sultanates in which Jai Singh played a leading part—later this same army was sent to campaign against the Gond kingdoms. For his part in these successful ventures Jai Singh was promoted to the rank of commander of 5000 and the Chatsu district in Ajmer was added to his kingdom. By defeating the Meo robber tribes in the north of Amber, Jai Singh further increased the size of his ancestral kingdom. In 1641 he subdued the rebellion of Raja Jagat Singh Pathania of the hill-state of Mau-Paithan (Himachal Pradesh).
Central Asian campaigns
In 1638 the fort of Kandahar was surrendered by its Safavid Persian commander, Ali Mardan Khan, to Shah Jahan. The emperor's son Shah Shuja, accompanied by Jai Singh, was sent to take possession of the important fort. To overawe the Persian Shah from interfering in this task, Shah Jahan assembled a 50,000 strong army in Kabul. On this occasion Jai Singh received the unique title of Mirza Raja from Shah Jahan, which had earlier been given to his grandfather Raja Man Singh I of Amber by Emperor Akbar.
In 1647, Jai Singh joined in Shah Jahan's failed invasions of Balkh and Badakhshan in Central Asia.
In 1649, in another blow to Mughal prestige—Kandahar was recovered by Shah Abbas II. In the ensuing Mughal-Safavid War the Mughals twice attempted to eject the Persians from Kandahar under the command of Prince Aurangzeb (in 1649 and 1652) —on both occasions Jai Singh was present as an army commander, but the attempts failed due to the lack of adequate artillery and poor marksmanship of the Mughal gunners.
A third grand attempt was made in 1653 under the command of Shah Jahan's oldest and favorite son Dara Shikoh, a rival of Aurangzeb, and again Jai Singh was sent with this army. Dara Shikoh's campaign was marred by his military incompetence, including poor military advisors, and frequent clashes with officers who had taken part in the earlier campaigns under Aurangzeb. He repeatedly taunted Jai Singh for those failures. But when his own campaign ended with the same result, the Mughals finally gave up all attempts to recover Kandahar.
Dara Shikoh continued his hostility towards Jai Singh on their return to Agra. No promotions or awards were given to the veteran general for skillfully covering the army's retreat. Instead Jaswant Singh of the rival Rathor clan was made commander of 6000 and received the superlative title of Maharaja.
Mughal succession war
In 1657, Emperor Shah Jahan became incapacitated due to a serious illness. Dara Shikoh's three younger brothers made preparations to seize the throne. Shah Shuja in Bengal and Murad in Gujarat crowned themselves emperors, but Aurangzeb cleverly declared his intention of merely rescuing his father for the sake of Islam. In the face of these triple dangers, Dara Shikoh now remembered Jai Singh—and the Rajput chief was made commander of 6000 and sent east along with Dara's son Sulaiman Shikoh and the Afghan general Diler Khan
They triumphed over Shah Shuja at the Battle of Bahadurpur (24 February 1658) and chased him back to Bengal (May). By that time Aurangzeb had won the Battle of Dharmat (15 April 1658) and the Battle of Samugarh (29 May 1658) and captured Agra (8 June). Jai Singh and his men were stuck far in the east while their homes and families in the west were at the mercy of Aurangzeb's troops—so Jai Singh and Diler Khan advised Sulaiman Shikoh to flee while they submitted to the new emperor. Jai Singh then advised Maharaja Jaswant Singh against helping Dara Shikoh to secure his position with Aurangzeb.