In India during the Axial Age appeared the Maurya Empire—a geographically extensive and powerful empire, ruled by the Mauryan dynasty from 321 to 185 BC. The empire was founded in 322 BC by Chandragupta Maurya through the help of Chanakya, who rapidly expanded his power westward across central and western India, taking advantage of the disruptions of local powers following the withdrawal by Alexander the Great. By 320 BC, the Maurya Empire had fully occupied northwestern India as well as defeating and conquering the satraps left by Alexander. Under Emperor Asoka the Great, the Maurya Empire became the first Indian empire to conquer the whole Indian Peninsula — an achievement repeated only twice, by the Gupta and Mughal Empires. In the reign of Asoka Buddhism spread to become the dominant religion in many parts of the ancient India.