[57] Arrian, i. 1, 12, 17. The precise locality of that steep road whereby Alexander crossed the Balkan, cannot be determined. Baron von Moltke, in his account of the Russian campaign in Bulgaria (1828-1829), gives an enumeration of four roads, passable by an army, crossing this chain from north to south (see chap. i. of that work). But whether Alexander passed by any one of these four, or by some other road still more to the west, we cannot tell. Having thus forced the mountain road, Alexander led his army over the chain of Mount Hæmus, and marched against the Triballi: a powerful Thracian tribe,—extending (as far as can be determined) from the plain of Kossovo in modern Servia northward towards the Danube,—whom Philip had conquered, yet not without considerable resistance and even occasional defeat. Their prince Syrmus had already retired with the women and children of the tribe into an island of the Danube called Peukê, where many other Thracians had also sought shelter. The main force of the Triballi took post in woody ground on the banks of the rivet Zyginus, about three days’ march from the Danube. Being tempted however, by an annoyance from the Macedonian light-armed, to emerge from their covered position into the open plain, they were here attacked by Alexander with his cavalry and infantry, in close combat, and completely defeated. Three thousand of them were slain, but the rest mostly eluded pursuit by means of the wood, so that they lost few prisoners. The loss of the Macedonians was only eleven horsemen and forty foot slain; according to the statement of Ptolemy, son of Lagus, then one of Alexander’s confidential officers, and afterwards founder of the dynasty of Greco-Egyptian kings.[58] [58] Arrian, i. 2.