Magadha, Kingdom of, central power of India from the 6th century BC to the 6th century AD . An ancient kingdom covering what is now the state of Bihâr, it rose to a position of dominance under its first great king, Bimbisara (reigned about 543-491 BC), and was further expanded by his son Ajatasatru (reigned about 491-459 BC). By the 4th century BC Magadha included most of northern India. Falling briefly under the sway of Alexander the Great and his Macedonian successors, it was conquered in 321 BC by Chandragupta Maurya, who made it the center of his Mauryan Empire. Although Magadha declined after the Mauryan dynasty died out in 185 BC, it was raised to new heights of glory under the Gupta dynasty (AD 320-550?), during whose rule a stable peace encouraged intellectual and artistic accomplishments. With the disintegration of the Gupta dynasty in the 6th century, Magadha lost its primacy as an Indian power. Temporarily revived under King Dharmapala (reigned about 770-810), it fell to the Muslims at the end of the 12th century, after which it became a mere province of the Delhi Sultanate. See also India.