The former Schwarz identifies with Nau, and the latter with Ura-tübe, a considerable city occupying a commanding position, strongly fortified, and distant from Khojent about 40 miles. It had been founded by Cyrus to serve as a bulwark against incursions of the Skythians. Alexander having quelled the attempted revolt of the Sogdians, crossed the Jaxartes, and inflicted a defeat on the Skythians, who had mustered in great force on their own side of the river. He pursued them as far as what Curtius calls the boundary-stones of Father Bacchus, which Schwarz has identified as a pass over Mogul-Tau, near Mursa-rabat, a post-station, 17 miles distant from Khojent. On the heels of this victory tidings reached Alexander of the terrible defeat and slaughter of his Macedonian troops by Spitamenes in one of the islands of the Polytimêtos, and he immediately started for Marakanda, and reached it after a march of three days. As the distance from Khojent to Samarcand is 172 English miles, this march, made in broiling heat, and through a country without roads, must have tried to the very utmost the powers of endurance of the Macedonian soldiers, some of whom were hoplites, wearing their brazen helmets, carrying their shields, and clad in mail. Spitamenes made his escape into the desert, and Alexander could only sate his vengeance by ravaging with merciless severity the beautiful valley through which the river flowed. Schwarz tells us that he searched in vain to discover the island which was the scene of the disaster, and it probably no longer exists. It must, however, he thinks, have been situated in the neighbourhood of Ziadin and Kermineh. Alexander, pursuing his way down the river, passed Bokhara, the Sogdian capital, and advanced as far as Karakul, beyond which the river disappears in the sands. He then retired for the winter to Zariaspa. Zariaspa has been taken to be another name of Baktra, but Schwarz shows that such an opinion is altogether untenable, and identifies it, for reasons not to be gainsaid, with Charjui, a place some six or seven miles distant from where the Oxus is now spanned by the bridge of the Trans-Caspian Railway.