- Matsya (also known as Machcha) was one of the sixteen Mahajanapadas (great kingdoms) that flourished in ancient India around the 6th century BCE. - Its territory roughly corresponded to the region of modern-day Jaipur, Alwar, and Bharatpur in Rajasthan. - The capital of the Matsya Mahajanapada was Viratanagara, modern Bairat, located near Jaipur.