Magadha was one of the 16 great kingdoms or mahajanapadas in India between the 6th and 4th centuries BCE. Apart from Asmaka or Assaka, all the other fifteen mahajanpadas were located in Northern India. Assaka was located in what is now present-day territory comprising Andhra Pradesh, Telangana, and Maharashtra.
The most remarkable king of the Haryanka dynasty of the Magadhan kingdom in the 6th century BC was Bimbisara, also known as Srenika. He ascended the throne in c 545 B.C. He was the first Indian ruler who conceived the idea of an extensive empire.
He embarked on a policy of imperialism by conquering the little kingdom of Anga which had its capital at Champa near modern Bhagalpur in Bihar. In ancient times, the port city of Champa was of substantial commercial significance.
Though Anga was the only conquest of Bimbisara, he strengthened his position by matrimonial alliances with other kingdoms. His marriage with Kosala Devi, a sister of Prasenjit of Kosala kingdom, brought him the part of Kasi (Varanasi). He was also married to Chellana, the daughter of Chetaka, the Licchavis king of Vaishali. Chetaka was the brother of Trishala, mother of Mahavir (founder of Jainism). Another wife of Bimbisara was Khema who was born into the royal family of Madra in central Punjab.
Bimbisara's capital was Raajgriha, the modern Rajgir in the Nalanda district of Bihar. A contemporary of Buddha Bibmisara was his follower. He had offered Buddha and his followers his favourite park and pleasure garden, Veluvana (Bamboo Grove) in Rajgriha for their residence.
Bimbisara was in diplomatic contact with Pushkarasarin, the ruler of Gandhara, whose kingdom also included Taxila.
Bimbisara was deposed, imprisoned and murdered by his son Ajatashatru in about 494 B.C.