Originally posted by set_raj
Actually in Shrimadh Bhagvad it is mentioned that Kalyavan was a Yavana..and whereas in other books it is mentioned that he had a boon..which I also find rather confusing...Yadavas were powerful cos of Shri Krishna and later during Ugrasen's rule Krishna and Balraam won so many battles and they killed so many demons and tyrant rulers...Yadavas grew stronger leap and bounds..all cos of Krishna..and this was the main reason also of Krishna to see all Yadavas are destroyed before going to his Abode as he knew later these Yadavas can become arrogant and tyrant cos of power..
My point was that at the time Kalyavan would have received such a boon, the Yadavas were Mathura based and rather weak. Nobody would be doing yagnas or tapasya to get boons to defeat them! Yeah, later on, due to the successes of Krishna & Balarama and the introduction of new warriors like Pradhyumna, Satyaki, Charudeshna, et al, they became as powerful as the Kurus. But that was not the case at the time Kalyavan would have made his request.
And if he was a Yavana, there is no way he could have gotten boons from Shiva or Brahma, since vedic meditation and scriptural info would have been alien to him.