Porus
Porus or Poros (from the Greek Πῶρος, Pôros) was a king of the Pauravas whose territory spanned the region between the Hydaspes (Jhelum) and Acesines (Chenab) rivers in what is now Punjab. Porus famously fought Alexander the Great in the Battle of the Hydaspes in 326 BC and it was generally believed by historians that he was defeated. Alexander was however greatly impressed by his adversary and not only reinstated him as a satrap of his own kingdom but also granted him dominion over lands to the north extending until the Hyphasis (Beas).
After Alexander's death in 323 BC, Porus was assassinated by one of Alexander's generals named Eudemus sometime between 321 and 315 BC.
Background
The only information available on Porus is of Greek origin. Historians however have reasoned that based on his name and the location of his domain, Porus was likely to have been a descendant of the Puru tribe mentioned in the Rig Veda.
The historian, Ishwari Prasad, noted that Porus might have been a Yaduvanshi Shoorsaini. He argued that Porus' vanguard soldiers carried a banner of Herakles whom Megasthenes—who travelled to India after Porus had been supplanted by Chandragupta—explicitly identified with the Shoorsainis of Mathura. This Herakles of Megasthenes and Arrian has been identified by some scholars as Krishna and by others as his elder brother Baladeva, who were both the ancestors and patron deities of Shoorsainis. Iswhari Prashad and others, following his lead, found further support of this conclusion in the fact that a section of Shoorsainis were supposed to have migrated westwards to Punjab and modern Afghanistan from Mathura and Dvārakā, after Krishna's demise and had established new kingdoms there.