The unrighteous king of Surasena Kingdom, viz Kansa was slain by Vasudeva Krishna. Kansa's wives "Asti" and "Prapti", where the daughters of Jarasandha, the king of Magadha. He attacked the kinsmen of Krishna. The Surasena Yadavas, consisting of the "eighteen younger branches of the Yadavas" with their 18000 brothers and cousins, arrived at the conclusion that even if they fight continually they still could be unable to do anything unto Jarasandha even in 300 years. They fled from Mathura, towards west. They rebuilt the old town of "Kusasthali"(see:Cortalim), and renamed it Dwaraka. It was a Yadava stronghold. Yet, due to the oppressions of Jarasandha, Yadavas where obliged to migrate further south, to "the mountains of Gomanta", measuring three "Yojanas" (a unit of length) in length. Within each yojana were established, 21 posts of armed men. And at intervals of each yojana were 100 gates with arches which were defended by valiant heroes engaged in guarding them. Innumerable Kshatriyas invincible in war, belonging to the eighteen younger branches of the Yadavas, were employed in defending these works. (2,14)