Probably from about the year 200 B.C., possibly from an even earlier period, the Romans used spurs, apparently the common prick spurs which remained in vogue until towards the middle of the thirteenth century A.D. Some half-a-century later, or about the year 150 B.C., there were issued in succession a series of Gaulish silver coins, the majority of which bore upon one side the impression of a horseman, though comparatively few showed the chariot at one time so generally represented on coins. This leads naturally to the inference that the popularity of the chariot was already waning. Chariots, however, continued to appear upon the gold coins made in imitation of the gold stater of Philip II. of Macedon, coins that bore on the face Apollo's head, on the reverse a two-horse chariot. Exceptionally fine horses, probably with Liberian blood in them, must have been owned by the Iberians and Celtiberians at about the period the Stoic philosopher Posidonius was travelling in Western Europe, and when he incidentally visited Spain—about the year 90 B.C. Posidonius himself remarks that the cavalry of the Iberians was trained to travel over mountains, adding that these horses too would crouch when told to, in order that their riders might mount or dismount with greater ease. A method to which this cavalry sometimes had recourse consisted in their mounting two men on one animal. Then, in the heat of action, one of the men would fight on foot, the other remaining by to defend him if hard pressed. The same philosopher tells us that the horses of the Parthians and Celtiberians “indeed were superior to all other breeds in fleetness and endurance.” CHAPTER IV Virgil on the points of a horse—Cæsar's invasion—Abolition of war chariots—Precursor of the horseshoe—Nero's 2000 mules shod with silver; Poppæa's shod with gold—The Ossianic and Cuchulainn epic cycles; Cuchulainn's horses—The Iceni on Newmarket Heath; early horse racing in Britain—Horses immolated by the Romans; white horses as prognosticators—Caligula's horse, Incitatus; Celer, the horse of Verus; the horse of Belisarius Virgil, whose famous “Georgics” was published about the year 29 B.C., incidentally shows how close the connection was that in his time existed between men and their horses—that is, in so far as the former would probably have gained comparatively few victories and made but little headway in civilisation had they not been materially helped by “man's friend and ally, the horse.”