Analysis of information sources in references of the Wikipedia article "Abhira dynasty" in Simple English language version.
Krishna belongs to a nomadic tribe of Abhiras known as Sāttvatas who inhabited the country near Mathura. These Sāttvatas or more properly the Yadavas of whom they were a branch were mentioned by Panini.
The Yādavas, mentioned in the Mahabharata, were pastoral kshatriyas among whom Krishna was brought up. The Gopas, whom Krishna had offered to Duryodhana to fight in his support when he himself joined Arjuna's side, were no other than the Yadavas themselves, who were also the Abhiras. In the Epics and the Puranas the association of the Yādavas with the Abhiras was attested by the evidence that the Yådava kingdom was" mostly inhabited by the Abhiras. In the Mahabharata it is mentioned that when the Yadavas (though belonging to the Abhira group) abandoned Dwaraka and Gujarat after the death of Krishna and retreated northwards under Arjuna's leadership, they were attacked and broken up.