Mahajanapadas were a set of 16 kingdoms in ancient India.
The total 16 Mahajanapadas are - Kashi, Kosala, Anga, Magadha, Vajji, Malla, Chedi, Vatsa, Kuru, Panchala, Machcha, Surasena, Assaka, Avanti, Gandhara and Kamboja.
It was found in Sutta Pitaka, a part of Tripitaka (early Buddhist literature), which is written in the Pali language.
Bimbisara (558-491 BC): Belonged to the Haryanaka dynasty was the first ruler of Magadha (543-492 BC) Mahajanpadas in sixth century BC.
Bimbisara founded the state of Magadha by bringing together a number of tribes and territories.
Bimbisara was the first ruler of Magadha Mahajanapadas in the sixth century BC.
Bimbisara was also known as Kshanik.
He expanded their empire by establishing matrimonial relations. He married Mahakoshla, sister of Koshal Naresh Prasenjit, Chellana, daughter of Chetak of Vaishali, and Princess Kshema of Madra Desh (modern Punjab).
Aajatshatru was the son of Bimbisara.
Hence, the first ruler of Magadha Mahajanapadas in the sixth century BC was Bimbisara.