The whole question of this spread of mercantile knowledge along the trade routes is so connected with the [.g]ob[=a]r numerals, the Boethius question, Gerbert, Leonardo of Pisa, and other names and events, that a digression for its consideration now becomes necessary.[290] {75} Even in very remote times, before the Hindu numerals were sculptured in the cave of N[=a]n[=a] Gh[=a]t, there were trade relations between Arabia and India. Indeed, long before the Aryans went to India the great Turanian race had spread its civilization from the Mediterranean to the Indus.[291] At a much later period the Arabs were the intermediaries between Egypt and Syria on the west, and the farther Orient.[292] In the sixth century B.C., Hecataeus,[293] the father of geography, was acquainted not only with the Mediterranean lands but with the countries as far as the Indus,[294] and in Biblical times there were regular triennial voyages to India. Indeed, the story of Joseph bears witness to the caravan trade from India, across Arabia, and on to the banks of the Nile. About the same time as Hecataeus, Scylax, a Persian admiral under Darius, from Caryanda on the coast of Asia Minor, traveled to {76} northwest India and wrote upon his ventures.[295] He induced the nations along the Indus to acknowledge the Persian supremacy, and such number systems as there were in these lands would naturally have been known to a man of his attainments. A century after Scylax, Herodotus showed considerable knowledge of India, speaking of its cotton and its gold,[296] telling how Sesostris[297] fitted out ships to sail to that country, and mentioning the routes to the east. These routes were generally by the Red Sea, and had been followed by the Phoenicians and the Sabaeans, and later were taken by the Greeks and Romans.[298] In the fourth century B.C. the West and East came into very close relations. As early as 330, Pytheas of Massilia (Marseilles) had explored as far north as the northern end of the British Isles and the coasts of the German Sea, while Macedon, in close touch with southern France, was also sending her armies under Alexander[299] through Afghanistan as far east as the Punjab.[300] Pliny tells us that Alexander the Great employed surveyors to measure {77} the roads of India; and one of the great highways is described by Megasthenes, who in 295 B.C., as the ambassador of Seleucus, resided at P[=a]tal[=i]pu[t.]ra, the present Patna.[301] The Hindus also learned the art of coining from the Greeks, or possibly from the Chinese, and the stores of Greco-Hindu coins still found in northern India are a constant source of historical information.[302] The R[=a]m[=a]yana speaks of merchants traveling in great caravans and embarking by sea for foreign lands.[303] Ceylon traded with Malacca and Siam, and Java was colonized by Hindu traders, so that mercantile knowledge was being spread about the Indies during all the formative period of the numerals.