The ancient name of द्वारकापुरी ; an island. It was emperor रेवत , son of आनर्त , the grandson of वैवस्वत मनु , who first built a city in कुशस्थली and ruled the country. Their genealogy; Descended from विष्णु thus: ब्रह्मा -- मरीचि -- कश्यप -- विवस्वान् -- वैवस्वत मनु -- शर्याति ( शय्याति )-- आनर्त -- रेवत . Certain पुराणस् state that it was आनर्त , who first built forts at कुशस्थली . It would not be incorrect to say that आनर्त built forts in this city first founded by his son रेवत . The city was sunk in the sea after a few years. Afterwards the region remained as a forest for long years. It was later on that श्री कृष्ण built द्वारका there. Following कृष्ण 's death the यादव dynasty got annihilated and the region was again swallowed by the ocean. द्वारका is believed to have been an island situated in the sea to the west of Gujarat. Even today there is a place called द्वारका on the coast of India to the west of Gujarat. (Devī Bhāgavata, 7th Skandha and Bhāgavata, 10th Skandha)