The process of empire building started Magadha under the Harsanka dynasty. This work was started by Bimbisara (545-494 B.C.). His symbol (surname) was ‘Srenik’. He established matrimonial relationship with Koshala, Baisali, Videha and Madra and thereby gained strength and prosperity. He got Kashi (Benaras) as a dowry from Koshala Kingdom. It was for this relationship the north and west border of Magadha came secured. Then he defeated Brahmadutta and conquered Anga. Their business through sea route was developed from this win. He was a reputed and active ruler. In his time Mahavira and Gautama Buddha propagated their religions.
After Bimbisara his son Ajatshatru sat on the throne. Probably he had killed his father to achieve the throne (498-462 B.C.). The king of Koshala was defeated by him in the battle and was bound to return back Kashi to him. He was engaged in a long war with Vajji democratic kingdom. From the Jain scripts we come to know that under the leadership of Lichchhavi King 36 republic states stood as one and fought the battles. Some historians described this as a fight between imperialists and the republican democrats. This war continued for 16 years. At last by using Mahasilakantaka he won the war.
In the beginning Ajatshatru was fond of Jainism but later on accepted Buddhism. To fight the battles properly he erected a fort in Pataliputra. During his time first conference of Buddhist was held. His successor Udayana established Pataliputra city. After him Aniruddha, Munda and Nagdasaka sat on the throne. At last by killing the last king of Haryanka dynasty Nagdasaka, one ministerial officer Sisunaga sat on the throne and started the Sisunaga dynasty (430 B.C.).