2. The mountain-valley, which in later times bore the name of Thessaly, was bounded to the west by Pindus, to the south by Othrys, to the east by Pelion and Ossa, and to the north by Olympus, under which name the ancient writers, for example Herodotus, also include the chain which in after-times (probably from an Illyrian word)(63) was called the Cambunian mount. The course of the Peneus is so situated as to divide the open plain to the south, the ancient Pelasgic Argos, from the mountainous district to the north; towards the north-east it breaks through the mountain-ridge, dividing Ossa from Olympus; here too the river creeps under the loftier heights of mount Olympus;(64) so that the path passes along the side of the more rugged and precipitous Ossa. This ravine was known by the ancient generic name of _Tempea_ or _Tempe_ (the _cut_, from τέμνω), and has been often poetically described, but seldom sufficiently considered as bearing upon the history of Greece.(65) Before entering the pass, the traveller crosses a small round valley, agreeably situated; at the end of which on the left hand, where the mountains approach one another on both sides, was the ancient fortress of Gonnus (or Gonni), distant 160 stadia from Larissa, the chief city of the plain.(66) From this point the mountains close upon one another more rapidly, until they rise on both sides of the glen in two rocky parapets, forming a gully, where in many places a path has been hewn along the river. About the middle of this path there stands now, upon a bold projection of Ossa, a fortress of Roman construction called Horæo-Castro, covering also a cross glen of that mountain: it was there probably that the strong-hold Gonnocondylum stood; which appears to have taken its name from the “windings” of the valley.(67) Not far from this spot is the narrowest part of the ravine, hardly 100 feet in width: which is stated in an inscription to have been fortified by L. Cassius Longinus, the proconsul and partisan of J. Cæsar; but, without the aid of fortification, a few armed men would probably have been able to stop the progress of a force many times their number. The region has nothing beautiful or agreeable in its appearance, but presents rather a look of savage wildness: the perpendicular masses of rock of the same kind of stone appear, as it were, to have been rent asunder, and are without any covering of trees or grass; the blackness of the shadows in the deep hollow, and the dull echoes, increase the gloominess of the impression: beneath bubble the silver waters of the Peneus (ἀργυροδίνης).(68) Not far from this narrow passage the defile opens towards the sea, to which the Peneus flows through marshes; and from hence may be seen the smiling country of Pieria, on the eastern side of Olympus, particularly the plains of Phila, Heracleum, and Leibethrum, which lead onwards to the southern parts of Macedonia.