Ajatasatru ruled from c. 492 BC to c. 460 BC. He was a king of the Magadha empire in north India. He was the son of King Bimbisara, the great monarch of Magadha. He was contemporary to Mahavira and Buddha.
Background
He took over the kingdom of Magadha from his father forcefully by imprisoning him. He fought a terrible war against the Vajjis/Lichhvis and conquered the once considered invincible democratic Vaishali Republic. He followed the policy of conquest and expansion. He defeated his neighbours including the king of Kosala; his brother occupied Kashi which was given to Bimbisara as dowry. This led to a war between Magadha and Kosala. Ajatshatru occupied Kashi and captured the smaller kingdoms. Ajatshatru's Magadha became the most powerful kingdom in Northern India and its power was felt far and wide.
Career
At the age of 20 he was married to Princess Padmavati. Once King Bimbisara decided to give gifts to his children (those born of Queen Chelna), he gave an 18 fold Divine Necklace to Hallakumara and one Sechanaka (watering) White elephant (pachyderm) to Vihallakumara, which cost more than half of Magadha. But as the king wanted to surprise Ashokcahandra by giving him the entire kingdom, he did not give anything to him on that day. But Ashokchandra, failing to understand his father, thought that the king would even give the entire kingdom to Halla and Vihallakumaras. Thus, he imprisoned his father in the prison of Rajgriha and enthroned himself as king of Magadha.