Sawai Jai Singh II was the founder of the city of Jaipur and the ruler of the Kachwaha dynasty in Rajasthan, India, during the early 18th century. He is known for his contributions to astronomy and architecture, establishing several observatories called Jantar Mantar in different cities, including Jaipur and Delhi. Jai Singh was also a skilled diplomat and military leader, known for his alliances with other regional powers. His reign marked a period of cultural and economic growth, and he is remembered for his efforts to modernize his kingdom while preserving its traditions.