A unique structure raised in 1724, now lies in the heart of Delhi's
commercial centre near Connaught place. This is the Jantar Mantar, one
of several astronomical observatories raised by Maharaja Jai Singh II of
Jaipur.
The various abstract structures within the Jantar Mantar are, in fact,
instruments that were used for keeping track of celestial bodies. Yet,
Jantar Mantar is not only a timekeeper of celestial bodies, it also
tells a lot about the technological achievements under the Rajput kings
and their attempt to resolve the mysteries regarding astronomy.
The Jantar Mantar of Delhi is only one of the five observatories built
by Sawai Jai Singh II, the other four being located at Jaipur, Varanasi,
Ujjain and Mathura. All of these were built as far back as AD 1724-1730
during the period generally known as the dark age of Indian history,
when the last great Mughal emperor Aurangzeb had died and the Mughal
Empire was rapidly declining.

During this period of turmoil, Muhammad Shah ascended the throne of the
Mughal Empire. As many enemies surrounded him, he sought the alliance of
the Hindu rulers. Of these, the most notable was Sawai Jai Singh II of
Amber, who came into limelight since the days of Aurangzeb. When Jai
Singh ascended the throne of Amber in 1699, he was barely eleven, but
sharp and shrewd far beyond his years.
The then Mughal emperor Aurangzeb was so impressed with the young ruler
that he gave Jai Singh II the title of 'Sawai', meaning one and a
quarter of an average man in worth. As Jai Singh repeatedly proved
himself a worthy ally of the Mughals, Muhammad Shah, who was seeking a
dependable ally, zeroed in on Jai Singh and duly raised him to the rank
of governor of Agra and later, of Malwa.