Definition: Porus, king of the area between the Hydaspes (Jhelum) and the Acesines rivers, in the Punjab, in the Indian subcontinent, met Alexander the Great at the Battle of the Hydaspes River, in June 326 B.C. Porus brought war elephants with him that terrified the Greeks and their horses. Monsoons proved more of an obstacle to the bowmen of the Indian than to the Macedonians who crossed the swollen Hydaspes on pontoons, and so Alexander's troops gained the upper hand while the elephants stampeded their own troops. King Porus surrendered to Alexander, but appears to have continued on as a satrap or viceroy, granted the land to the east of his own kingdom, until he was killed between 321 and 315 B.C. Alexander's victory brought him to the eastern border of the Punjab, but he was prevented by his own troops from going into the kingdom of Magadha.
Sources include: Mauryas, by Jona Lendering and Alexander the Great in the Punjab.
Ancient writers about Porus and Alexander the Great at the Hydaspes, who were, unfortunately, not contemporaries of Alexander, are: Arrian (probably best, based on the eyewitness acount of Ptolemy), Plutarch, Q. Curtius Rufus, Diodorus, and Marcus Junianus Justinus (Epitome of the Philippic History of Pompeius Trogus).
Examples:
It was during the battle against King Porus that Alexander's famous horse, Bucephalus, was killed.
