During the Iron Age, (between 1000-500 B.C.) there came up 16 powerful mahajanapada (kingdoms or states) in the Gangetic Plains of North India
. Vedic Literature including the itihasaas make repeated mentioning of these states. These were Kasi, Kosala, Amga, Magadha, Vajji, Malla, Chhedi, Valsa, Kuru, Panchaala, Matsya, Surasenam, Achhakam, Avanti, Gandhara and Kamboj. These kingdoms covered a very extensive chunk of north India
from the modern Bangladesh in the east to the modern Afghanistan in the west through the Gangetic plains. The biggest kingdoms among these were Magadha, Kosalam, Kuru, and Gandhara. It was during this period that the Upanishads and other texts as well as the religions of Buddhism and Jainism had their appearance. These two religions made use of the common man’s language of the Prakrit for their teachings rather than the Sanskrit
used by the Vedic Hinduism. While the Jainism remained within the limits of India
, the Buddhism went beyond India
and spread to other parts of Asia.