Ἀλεξάνδρου ἀνάβασις 5.19.6

5.19.6

οὗτος ὁ ἵππος ἐν τῇ Οὐξίων χώρᾳ ἀφανὴς ἐγένετο Ἀλεξάνδρῳ, καὶ Ἀλέξανδρος προεκήρυξεν ἀνὰ τὴν χώραν πάντας ἀποκτενεῖν Οὐξίους, εἰ μὴ ἀπάξουσιν αὐτῷ τὸν ἵππον· καὶ ἀπήχθη εὐθὺς ἐπὶ τῷ κηρύγματι. τοσήδε μὲν σπουδὴ Ἀλεξάνδρῳ ἀμφʼ αὐτὸν ἦν, τόσος δὲ Ἀλεξάνδρου φόβος τοῖς βαρβάροις. καὶ ἐμοὶ ἐς τοσόνδε τετιμήσθω ὁ Βουκεφάλας οὗτος Ἀλεξάνδρου ἕνεκα.

He was then conducted to Alexander, who, on learning that Meroës was approaching with him, rode forward in front of his line with a few of the Companions to meet him. Then reining in his horse he beheld with admiration the handsome person and majestic stature of Poros, which somewhat exceeded five cubits. He saw, too, with wonder that he did not seem to be broken and abased in spirit, but that he advanced to meet him as a brave man would meet another brave man after gallantly contending with another king in defence of his kingdom. Then Alexander, who was the first to speak requested Poros to say how he wished to be treated. The report goes that Poros said in reply, " Treat me, O Alexander ! as befits a king ; " and that Alexander, being pleased with his answer, replied, " For mine own sake, O Poros ! thou shalt be so treated, but do thou, in thine own behalf, ask for whatever boon thou pleasest," to which Poros replied that in what he had asked everything was included. Alexander was more delighted than ever with this rejoinder, and not only appointed Poros to govern his own Indians, but added to his original territory another of still greater extent. Alexander thus treated this brave man as befitted a king, and he consequently found him in all respects faithful and devoted to his interests. Such, then, was the result of the battle in which Alexander fought against Poros and the Indians of the other side of the Hydaspes in the month of Mounychion of the year when Hegemon was archon in Athens.
Alexander founded two cities, one on the battlefield, and the other at the point whence he had started to cross the river Hydaspes. The former he called Nikaia in honour of his victory over the Indians, and the other Boukephala in memory of his horse Boukephalas, which died there, not from being wounded by any one, but from toil and old age, for he was about thirty years old, and had heretofore undergone many toils and dangers along with Alexander. This Boukephalas was never mounted by any one except Alexander only, for he disdained all other riders. He was of an uncommon size and of generous mettle. He had by way of a distinguishing mark the head of an ox impressed upon him, and some say that from this circumstance he got his name. But others say that though he was black, he had on his forehead a white mark which bore a close resemblance to the brow of an ox. In the country of the Ouxians this horse disappeared from Alexander, who sent a proclamation through the land that he would kill all the Ouxians if they did not bring him his horse, and brought back he was immediately after the proclamation had been issued—so great was Alexander's attachment to his favourite, and so great was the fear of Alexander which prevailed among the barbarians. Let so much honour be paid by me to this Boukephalas for Alexander's sake.