=11.= Turning to the north and east, Alexander now sought the grand contest which was to transfer to him the dominions of Cyrus. He had purposely given Darius time to collect the entire force of his empire, so that one battle might decide its fate. The battle of Arbela (B. C. 331, Oct.) has been described in Book II. As its result the three capitals, Susa, Persep´olis, and Babylon, surrendered almost without resistance; and Alexander might, without further effort, have assumed the pomp and ease of an Oriental monarch. But his restless spirit carried him on to the conquest of the eastern provinces and India. He first marched into Media, where Darius had rallied the remnants of his forces to oppose him, but on his approach the dethroned king fled through the Caspian Gates to Bactria. Before Alexander could overtake him, he was murdered by his rebellious satrap, Bessus, who assumed the title of king of Persia. =12.= The Greek mercenaries of Darius, who had formed his most effective force, were now added to the army of the conqueror. From province to province Alexander marched, receiving submission and organizing governments. Bessus fled into Sogdiana, but was taken, and suffered a cruel death for his treason and usurpation. A new city of Alexandria was founded on the Jaxartes; and having chastised the Scythians to the northward, the conqueror returned to Bactria, where he spent the winter of 329 B. C. =13.= The genius of Alexander began to be disgraced by the pride and unscrupulous cruelty of an Eastern king. He adopted the Persian dress and ceremonial, and required his courtiers to prostrate themselves before him, as to a divinity rather than a mortal. He had already put to death his friend Philo´tas, on an unproved charge of plotting against his life; and the aged Parme´nio, father of Philotas, was subjected without trial to a similar fate. At Bactra, in a drunken revel, Alexander murdered his friend Clitus with his own hand. =14.= During his two years’ war against Sogdiana, Alexander captured a mountain fortress, where Oxyar´tes, a Bactrian prince, had deposited his family. Roxa´na, one of the princesses, became the wife of the conqueror. In the spring of 327 B. C., the Macedonian army crossed the Indus and invaded the Punjab. No resistance was encountered until it reached the Hydas´pes, where Porus, an Indian king, was drawn up with his elephants and a formidable body of men. An obstinate battle resulted in the defeat and capture of Porus; but his brave spirit so commanded the respect of his conqueror, that he was permitted to retain his kingdom.