The motley composition of such a host has been described in a former chapter. Each nation was armed and equipped after its own fashion, and served in a body, often under a distinct commander. The army marched through Asia in a single column, which was not, however, continuous, but was broken into three portions. The first portion consisted of the baggage animals and about half of the contingents of the nations; the second was composed wholly of native Persians, who preceded and followed the emblems of religion and the king; the third was made up of the remaining national contingents. The king himself rode alternately in a chariot and in a litter. He was preceded immediately by ten sacred horses, and a sacred chariot drawn by eight milk-white steeds. Round him and about him were the choicest troops of the whole army, twelve thousand horse and the same number of foot, all Persians, and those too not taken at random, but selected carefully from the whole mass of the native soldiery. Among them seem to have been the famous “Immortals”--a picked body of 10,000 footmen, always maintained at exactly the same number, and thence deriving their appellation. The line of march from Sardis to Abydos was only partially along the shore. The army probably descended the valley of the Hermus nearly to its mouth, and then struck northward into the Caicus vale, crossing which it held on its way, with Mount Kara-dagh (Cane) on the left, across the Atarnean plain, and along the coast to Adramytium (Adramyti) and Antandros, whence it again struck inland, and, crossing the ridge of Ida, descended into the valley of the Scamander. Some losses were incurred from the effects of a violent thunderstorm amid the mountains; but they cannot have been of a any great consequence. On reaching the Scamander the army found its first difficulty with respect to water. That stream was probably low, and the vast host of men and animals were unable to obtain from it a supply sufficient for their wants. This phenomenon, we are told, frequently recurred afterwards; it surprises the English reader, but is not really astonishing, since, in hot countries, even considerable streams are often reduced to mere threads of water during the summer.