This power of invention was all the more impressive for being a break with the Persian past. The Persians had borrowed their skills from their subjects, but the Greeks brought their own with them and then created more. The golden age of experimental Greek science under the patronage of the Ptolemies in Egyptian Alexandria is the purest tribute to the Greeks' gifted intellect, for no Persian ever calibrated a catapult, studied human anatomy, applied steam power to toys or divided the world into zones of climate. If Greek science was for too long the follower of Aristotle's dogmatism, always more theoretical than applied, it was nonetheless the symptom of a new mental liveliness. The financial exploitation of Egypt was a matter for Greeks, as the Pharaohs had already realized; under the Ptolemies in Alexandria, taxation, agriculture, improved canals, a coinage and commercial law helped to open a new economy to the Greek world. Visiting Greek doctors took the study of human anatomy far beyond Egyptian magic; the royal library encouraged the birth of classical philology and the deadening rise of textual scholarship. Whereas Babylon had been Asia's intellectual centre, the Greeks took the Babylonian records of astronomy and deduced the precession of the equinoxes which no compiler had ever detected; while a Babylonian wrote a book on the magical properties of stones, a Greek in the Successor's new Babylonian capital was arguing that the earth went round the sun and that the tides must be affected by the phases of the moon. Babylonians treated the particular, but the Greeks saw the general, and it was only to be expected that the liveliest political culture in the world should influence local government, the form of a Babylonian decree and the phrasing of a Jewish manifesto. The Greeks had an elegant mathematical theory and the power of abstract reasoning; a simple cell for electroplating silver on to copper has been found in Parthian Babylonia, and it is natural to credit its invention to a Greek.

To the tribes and villages of Iran, these skills must have appeared in the light of rifles and telescopes to their first Indian observers. The Greeks had more fundamental weapons, their art and their language, the two skills which still impress the classical past on an industrial world. To carve and to think in Greek was to work in a finer and more sensitive idiom, for it was well said by a Roman in the age of disputed theologies that if he started to discuss the Trinity in Latin, he could not avoid any one of three grave heresies. These new tools opened up a new world; there is no written history of the hellenization of the upper satrapies, but there are their arts and a few inscriptions and these are perhaps more revealing than mere events.

In Iran, Alexander had left Greek as the one written language. No Iranian dialect was literate and so the Persians' lame Aramaic was continued for native administration. With the annoying persistence of a pidgin jargon its script flourished far and long as a result, passing into Khwarezm beyond the Oxus where it served as the first native alphabet five hundred years after Alexander, and then as far as China where it was inscribed centuries later on the Heavenly Temple in Peking. It was no competitor for serious thought. Although the long tradition of the Iranian minstrel continued to flower in the professional gosans who sang at the Parthians' court, In Iran Greek was the only language for written poems and for the education of soldiers in each Alexandria; so the Greek classics appealed to the East with an impact which has only since been equalled by popular songs of the modern West. At the palace of Nisa, court of the Parthian kings on the lower Oxus, Greek plays were performed before an audience of former nomads, while among the palace documents directions have been found for the making of a mask for a tragic actor. In neighbouring Armenia, verses of Euripides were inscribed, perhaps as a school text, at a time when the province was ruled by an independent Iranian king; in Roman times, the tale of Castor and Pollux was known in the Swat highlands above the Indus; in the Punjab, five hundred years after Alexander, Indian Buddhists still carved the tale of the Trojan Horse alongside the life of their Buddha, a theme which is now known to have passed to them directly from Alexander's heirs in the neighbouring Greek kingdom of Bactria. Homer was always said to have been translated into an Indian language, and the extraordinary find of inscriptions in Ceylon which appear to discuss him together with Plato, Aristotle and Alexander in their Indian names more than five hundred years after Greek rule in Iran had ended should remove any doubts that the fate of Greek poetry in the East was brief or insignificant. When the Greek kingdoms fell, the Persian Gulf traders could still carry their legacy east by ship. The Persian kings had first settled Ionian Greeks as sailors in the ports near Susa, and their persistent Greek culture is the background to the Greek after-glow in western India.

The same is true of art. The coins and the silver trappings of the Greeks in Bactria are of the highest craftsmanship, and at the Parthians' palace of Nisa, their profound effect on Iranian neighbours can now be appreciated. Iranian drinking-cups were carved with the legend of Dionysus; Aphrodite, Heracles and Hera were sculpted in marble; the palace included a gymnasium and columns with acanthus leaves, a style which left its trace in the Punjab's art for another four hundred years. These kings were the sons of Iranian nomads, and yet they took to Greek art like Czarist Russians playing with French civilities; their taste had an astonishingly long history both among the nobles and the alternative culture of the nomads. Greek influence can be traced in the pattern of the oriental carpets found in central Asia of the same broad date as Nisa, again in the sculpture and architecture of an Iranian palace and temple at Surkh Kotal in Afghanistan a century after nomads had seized Greek Bactria, in the coins placed for Charon in the mouths of the dead beyond Alexander's north-east frontier and in the clay figures made in Samarkand some seven hundred years after the last Greek Bactrian king. Through Alexander's planned sea route from Egyptian Alexandria along the Persian Gulf to the river Indus the Greek art of Alexandria reached to the Punjab and outer Iran for at least five hundred yean; its designs may have helped the long life of Greek art in the area, and they certainly influenced the first carved Buddhist reliefs of north-west India. They had also come by the route which Alexander had determined to reopen.

And yet the hellenization of Iran was not deep or wide enough for permanent results. It was competing with an alternative, the Iranian nobility to whom a town was more the sum of its great families than a self-governing citizenry in an expanse of royal land. To these Iranians the family was life's one continuity, marked out by genealogies and rigid rule of precedence; a culture which spread through cities and administrators could not work down through their looser forms of rural government. Already at Nisa, the Parthians' documents were written in Aramaic, not Greek, and the courtiers' names were all Iranian, while the old words of rural Iranian government continued unchanged, the food-levy for the king's table, the land tax and the village commissioner, the satrapies and the baronial castles. 'Whosoever shall compel you to go with him a mile, go with him twain'; the word which Christ used for this requisitioning in hellenized Judaea was the Persians' old word for forced service on the stations of their Royal Road. In the country, Alexander had not come to change. His empire of vast spaces and wooded mountains could not be travelled swiftly or cheaply by centralized officials, so he chose to balance the old Persian forms. The new Greek cities were his chosen points of loyalty among tribesmen and desert-chieftains and once those cities fell to nomads or to the stronger pull of family allegiance, Iran had only the memories of Persian rule on which to feed; it was not by chance that the design of the throne of Achaemenid Persia lived on under Greek rule in the royal art of upper Iran. Persia, moreover, was still prepared to step back into her past, for Alexander's Successors had left the Persians' mountainous home province to Persian client-kings, and naturally, they had made no parade of hellenism. Five hundred years after Alexander, it was from this 'deep south' of Iranian feeling that the great Persian revival began, with a new line of kings, who at once brought back the titles of Darius's Empire. But this new Persia's triumphs were also inscribed on rock in an official Greek translation. Trapped between nomads and tribal barons, the heirs to Alexander's Greek cities had at last given way to a Persian court of country squires, but the embers of hellenism were still seen to glow in the brighter fire of Sassanid Persia.