In the 2nd century BCE, it was probably, a spoken vernacular, in the ancient state of Surasena.
Among all the Prakrits, it is most closely related to the Classical Sanskrit.
It is derived from the Old Indo Aryan dialect of Madhyadesha, on which Classical Sanskrit was mainly based.
It's descedents include languages of the Hindi belt, Central Zone of modern Indo-Aryan or Hindi languages, standard registers of the Hindustani language based on the Delhi dialect.