The valley of Laghman must always have been a populous valley. From the north the snow-capped peaks of Kafiristan look down upon it, and from among the forest-clad valleys at the foot of these peaks two important river systems take their rise, the Alingar and the Alishang, which, uniting, join the Kabul River in the flat plain, where villages now crowd in and dispute each acre of productive soil. It is difficult to reach the Laghman valley from the west. The defiles of the Kabul River are here impassable, but they can be turned by mountain routes, and Alexander's force, which included the Hyspaspists, who were comparatively lightly armed, with the archers, the "companion" cavalry and the lancers, was evidently picked for mountain warfare. The heavier brigades were with Hyphæstion who struck out by the straightest route for Peukelaotis, which has been identified with an ancient site about 17 miles to the north-east of Peshawur on the eastern bank of the Swat River, and was then the capital of the ancient Gandhara. We are told that Alexander's route was rugged and hilly, and lay along the course of the river called Khoes. Rugged and hilly it certainly was, but the Khoes presents a difficulty. He could not actually follow the course of the Kabul River (Kophen) from the Kabul plain because of the defiles, but he could have followed that river below Butkak to the western entrance of the Laghman valley where it unites with the Alingar, or Kao, River. It is impossible to admit that he reached the Kao River after crossing the Kohistan and Kafiristan, and then descended that river to its junction with the Kabul. No cavalry could have performed such a feat. Geographical conditions compel us to assume that he followed the Kabul River, which is sometimes called Kao above the junction of the Kao River.