The Maurya Empire was a geographically extensive Iron Age historical power in ancient India, ruled by the Mauryan dynasty from 322 to 185 BCE. Originating from the kingdom of Magadha in the Indo-Gangetic plains (modern Bihar, eastern Uttar Pradesh) in the eastern side of the Indian subcontinent, the empire had its capital city at Pataliputra (modern Patna). The Empire was founded in 322 BCE by Chandragupta Maurya, who had overthrown the Nanda Dynasty and rapidly expanded his power westwards across central and western India, taking advantage of the disruptions of local powers in the wake of the withdrawal westward by Alexander the Great's Macedonian armies. By 320 BCE the empire had fully occupied Northwestern India, defeating and conquering the satraps left by Alexander.
The Maurya Empire was one of the world's largest empires in its time, and the largest ever in the Indian subcontinent. At its greatest extent, the empire stretched to the north along the natural boundaries of the Himalayas, and to the east stretching into what is now Assam. To the west, it conquered beyond modern Pakistan, annexing Khorasan, Balochistan, south eastern parts of Iran and much of what is now Afghanistan, including the modern Herat and Kandahar provinces. The Empire was expanded into India's central and southern regions by the emperors Chandragupta and Bindusara, but it excluded a small portion of unexplored tribal and forested regions near Kalinga (modern Odisha), until it was conquered by Ashoka. Its decline began 60 years after Ashoka's rule ended, and it dissolved in 185 BCE with the foundation of the Sunga Dynasty in Magadha.
Under Chandragupta, the Mauryan Empire conquered the trans-Indus region, which was under Macedonian rule. Chandragupta then defeated the invasion led by Seleucus I, a Macedonian general from Alexander's army. Under Chandragupta and his successors, internal and external trade, agriculture and economic activities, all thrived and expanded across India thanks to the creation of a single and efficient system of finance, administration, and security.
After the Kalinga War, the Empire experienced half a century of peace and security under Ashoka. Mauryan India also enjoyed an era of social harmony, religious transformation, and expansion of the sciences and of knowledge. Chandragupta Maurya's embrace of Jainism increased social and religious renewal and reform across his society, while Ashoka's embrace of Buddhism has been said to have been the foundation of the reign of social and political peace and non-violence across all of India. Ashoka sponsored the spreading of Buddhist ideals into Sri Lanka, Southeast Asia, West Asia and Mediterranean Europe.
The population of the empire has been estimated to be about 50-60 million making the Mauryan Empire one of the most populous empires of the time.