Jai Singh II (3 November 1688 – 21 September 1743) popularly known as Sawai Raja Jai Singh was the 29th Kachwaha ruler of the Kingdom of Amber, who later founded the fortified city of Jaipur and made it his capital. He was born at Amber, the capital of the Kachwaha. He became ruler of Amber at the age of 11 after the death of his father, Raja Bishan Singh on 31 December 1699.
Initially, Jai Singh served as a vassal of the Mughal Empire. He was given title of Sawai by the Mughal Emperor Aurangzeb before the siege of Khelna in Deccan. "Sawai" means one and a quarter times superior to his contemporaries. He received title of Maharajah Sawai, Raj Rajeshwar, Shri Rajadhiraj in the year 1723, This was in addition to title of Saramad-i-Rajaha-i-Hind conferred on him on 21 April 1721
In the later part of his life, Jai Singh broke free from the Mughal hegemony, and to assert his sovereignty, performed the Ashvamedha sacrifice, an ancient rite that had been abandoned for several centuries. He moved his kingdom's capital from Amber to the newly-established city of Jaipur in 1727, and performed two Ashwamedha sacrifices, once in 1734, and again in 1741.
Jai Singh had a great interest in mathematics, architecture and astronomy. He commissioned the Jantar Mantar observatories at multiple places in India, including his capital Jaipur. He had Euclid's "Elements of Geometry" translated into Sanskrit.
The situation on his accession
When Jai Singh acceded to the ancestral throne at Amber, he had barely enough resources to pay for the support of 1000 cavalry.This abysmal situation had arisen during the previous 96 years, coinciding with the reign of the Mughal Emperor Aurangzeb. The Jaipur kings had always preferred diplomacy over arms in their dealings with the Mughals, since their kingdom was located so close to the Mughal power centers of Delhi and Agra.
Six months after his accession, Jai Singh was ordered by Aurangzeb to serve in the Deccan Wars. But there was a delay of about one year in his responding to the call. One of the reason for this was that he was ordered to recruit a large force, in excess of the contingent required by his mansab. He also had to conclude his marriage with the daughter of Udit Singh, the nephew of Raja Uttam Ram Gaur of Sheopur in March, 1701. Jai Singh reached Burhanpur on 3 August 1701 but he could not proceed further due to heavy rains. On 13 September 1701 an additional cut in his rank (by 500) and pay was made. His feat of arms at the siege of Khelna (1702) was rewarded by the mere restoration of his earlier rank and the title of Sawai (Sawai-meaning one and a quarter, i.e. more capable than one man). When Aurangzeb's grandson Bidar Bakht deputed Sawai Jai Singh to govern the province of Malwa (1704), Aurangzeb angrily revoked this appointment as jaiz nist (invalid).
Dealings with the later Mughals
The death of Aurangzeb (1707) at first only increased Jai Singh's troubles. His patrons Bidar Bakht and his father Azam were on the losing side in the Mughal war of succession. Sawai Jai Singh formed an alliance with the Rajput states of Mewar (matrimonially) and Marwar, which were done to form an alliance against Mughal Emperor Bahadur Shah I. Zulfiqar Khan appointed Jai Singh to govern the important provinces of Agra and Malwa. In Agra he came into conflict with the sturdy Jat peasantry.
Jai Singh and the Marathas
The Kachwaha ruler was appointed to govern Malwa three times between 1714 and 1737. In Jai Singh's first viceroyalty (subahdar) of Malwa (1714–1717), isolated Maratha war-bands that entered the province from the south (Deccan) were constantly defeated and repulsed by Jai Singh. In 1728, Peshwa Baji Rao defeated the Nizam of Hyderabad, part of the Mughal Deccan (treaty of Sheogaon, February 1728). With an agreement from Baji Rao to spare the Nizam's own domains, the Nizam allowed the Marathas a free passage through Berar and Khandesh, the gateway into Hindustan. The Marathas were then able to plant a permanent camp beyond the southern frontier of Malwa. Following the victory of the Peshwa's brother, Chimaji Appa, over the governor of Malwa Girdhar Bahadur on 29 November 1728, the Marathas were able to convulse much of the country beyond the Southern borders of the Narmada.