In the Iranian epic Kūshnāma, there is a rather interesting story that recounts how the inhabitants of B.sīlā cross-breed their domesticated horses with a magical horse living in the sea in order to obtain fine-bred ones. What is even more interesting is that similar accounts are also seen in many of other classical Perso-Arabic works and Chinese sources. The regions that such events took place in mainly spread over Central Asia and western China while in Kūshnāma, the story happens in B.sīlā, a legendary kingdom with its historical prototype being Silla. By sorting out certain records of how ancient people sought fine horses by cross-breeding domesticated horses with wild horses that inhabited mountains and waters within Chinese sources and classical Muslim works, and comparing these accounts with similar plot lines as depicted in Kūshnāma, this paper attempts to elucidate that the story in Kūshnāma is a result of flourishing land and maritime exchanges between East Asia and West Asia during ancient and medieval times, rather than a purely literary fiction. It was not only influenced by the horse culture that thrived over the Eurasian Steppe, but the story is also coincidentally in accordance with the fact that the nomadic zone which lies within the central Eurasian continent extends as far as the Korean Peninsula in northeast Asia.