Abhira
The Abhira were a legendary  people mentioned in Ancient Indian Epics and Scriptures as early as the Vedas. The Bhāgavata religion was considered primarily as the religion of the Abhiras (Ahirs) and Krishna himself came to be known as an Abhira (Ahir). In the Mediaeval literature, Krishna is called an Abhira (Ahir). The Abhira (Ahir) were named Gopa when they protected the cows, and Gopal when they tended and grazed the cows. In the period (from 500 B.C. to 1 B.C.) when the Pali language was prevalent in India, the word 'Gopal was modified to 'Goal' and by further modification it took the form of Gwal. This has been aptly described by an unknown poet in a verse that" due to rearing cattle, the Yadav are called 'Gopa' and after being called 'Gopal', they are called 'Gwal'.