In the meanwhile, what could not be copied from Rome would simply have to be stolen. For more than a century, the extortion of danger money from their western neighbour had lain at the heart of the Sasanians’ foreign policy. The days of beating off Roman invasions were long gone. The last serious attempt made by a Caesar to overthrow the House of Sasan had taken place back in AD 363, under the command of a would-be Alexander named Julian, and had ended with the death of the emperor himself, and the imposition upon his successor of gratifyingly humiliating peace terms. From that moment on, the Roman high command had come to accept a painful and unsettling truth: Persia could not be beaten. To continue ignoring that lesson would result only in an endless haemorrhaging of blood and gold. Cheaper, in the long run, simply to purchase coexistence. So it was, to the delight of a succession of Sasanian monarchs, that they had found themselves able to screw out of their great enemy what the Romans, with a fastidious show of delicacy, termed “subsidies,” and what the Persians, amid much self-congratulatory clamour, termed “tribute.” Who, for instance, had helped to fund Peroz’s programme of fortifications along the northern frontier? Caesar. Who had helped to pay his ransom? Caesar. Who had contributed gold towards his final expedition? Caesar. Yet it was true as well that the annihilation of Peroz’s army, and of its calamitous aftermath, had not gone unremarked in the council chambers of the West. In 501, when Kavad found himself under pressure from the Hephthalites to pay off the dues owed to them for their backing, and wrote to the emperor of the Romans, a one-time bureaucrat and notorious miser by the name of Anastasius, demanding what he euphemistically termed a “loan,” Anastasius refused. Clearly, Caesar’s advisers had calculated that Iranshahr was now a broken reed. This, for Kavad, was a most ominous development. For a century and more, the intimidating reputation of Persian arms had served to reap the House of Sasan prodigious benefit; yet now, if Kavad were to allow the ink-spotted accountants of Rome to call his bluff, not only would the Hephthalites remain unpaid, but his own prestige, and that of his entire empire, would suffer a yet further body-blow.
The Shahanshah, however, was hardly a man to allow a good crisis to go to waste. Peril, in his philosophy, existed solely to be turned to advantage. The Hephthalites could be recruited as mercenaries. The nobility, rather than being left to snap and tear at one another, and at the heels of the king himself, could instead be recruited to the common cause. All the seething religious antagonism that was racking Kavad’s empire could be dissolved, so he trusted, upon a summons to punish the Romans. Iranshahr may have been bloodied, but it remained what it had always been: a state powerfully geared to war. Not all the repeated humiliations inflicted by the Hephthalites had served to diminish the confidence felt by Kavad in his killing-machine: for the paradox was, as he well knew, that his armies were far better suited to savaging the wealthy and globe-spanning empire of Rome than they were to crushing impoverished nomads. Whatever else might be said about the Romans, they were at least civilised. They had cities that could be put under siege and armies that were not forever melting away. Above all, unlike the Hephthalites, they lay conveniently ready to hand: not lurking beyond those regions where royal authority was at its weakest, but right where the Shahanshah wanted them, directly on the doorstep of the land that constituted both his ultimate powerbase, and the surest guarantee of Iranshahr’s rank as a superpower.
“The Heart of Iran,” it was called; and yet this land was not Persia, nor anywhere else inhabited by the Aryan people. Follow the trunk road that led from beyond the easternmost province of the empire—Khorasan, as it was known—and continue through Parthia and Media to the great range of mountains, the Zagros, that formed the western rampart of the plateau of Iran, and the traveller would then start to descend, through many twists and turns, to a very different world. Eragh, the Persians called it—the “Flat Land.” The contrast with the upland regions of the empire could hardly have been more striking. Unlike Iran, where the cities planted by a succession of kings served only to emphasise the immense emptiness of the salt flats, or the deserts, or the mountains, the lowlands revealed an immense monotony of crops and brick. Whether spreading fields of barley, or smudges of brown smoke on the horizon, the tell-tale smears of urban sprawl, here were the marks of a landscape as intensively exploited as any in the world. All the gold and pearls in the imperial treasury were not as precious to the Persian monarchy as this, the truest jewel in its crown: for nowhere was more dazzlingly fecund, more blessed with fertile soil. Westwards from Mesopotamia, or “The Land Between the Rivers,” as the Greeks called the region, there stretched nothing except for sand; but the two great rivers themselves, the fast-flowing Tigris and the sluggish Euphrates, had served between them to make what would otherwise have been fiery desert bloom.
Not unaided, however. Human muscle had been scoring the mud steppes since the dawn of time—but never had there been quite such enthusiastic sponsors of irrigation as the House of Sasan. If royal power, in the eastern provinces of Iranshahr, was a thing of often shimmering insubstantiality, then in the West it had always been wielded with an iron fist. Massive labour gangs, funded and controlled directly from the imperial centre, had toiled for centuries to ensure that the wealth of Mesopotamia was exploited to the full. Immense effort was required simply to ensure that the canals did not silt up, that the rivers did not flood, that all the fields and factories did not degenerate back into swamps. The Persian monarchy, though, had achieved more than merely keeping the sludge and the whining mosquitoes at bay: it had expanded the network of canals on a truly colossal scale. Most were simple irrigation channels, sliced in squares across the fields; but some, the most grandiose, were as wide and deep as the Euphrates itself. Kavad himself had commissioned the excavation of a canal that promised to be the largest that Mesopotamia had ever seen: testimony to the implacable resolve of the crown, even amid crisis and financial meltdown, not to stint on its engineering budget. Some investments were always worth the expense. Once completed, the new canal would provide fresh water for a whole new swath of Mesopotamia. Hitherto barren soil would flourish; the population would swell; cities would sprout and grow. The economy, as it had done ever since the conquest of the lowlands by the House of Sasan, would continue to boom.65
Only follow the money. Rare was the Shahanshah who had failed to sniff majesty in the scent of the Mesopotamian mud. Even Ardashir himself, the original conqueror of this land back in AD 226, had quickly abandoned any notion of trying to rule it from Istakhr, venerable hometown of his dynasty though it was. The cockpit of Iranshahr, from his reign onwards, had lain instead on the banks of the Tigris. Ctesiphon—a sprawling agglomeration of once-distinct towns and villages ringed by bristling walls and dominated by the towering arches of a colossal royal palace—was certainly no stranger to such a role. By establishing its capital there, the House of Sasan had consciously planted its banner amid the rubble of countless former regimes. Opposite, for instance, on the far bank of the Tigris, lay Seleucia—a city named after one of Alexander’s generals. Once the haughty epitome of Greek power and self-confidence, all its streets and palaces had long since been lost to sand, and only gibbets now stood upon its walls. Ctesiphon itself, at the time of its capture by Ardashir, had been the capital of the Parthian kings. This pedigree—reinforced by the Sasanians’ own lavish building projects and the prodigious growth of its population—had served to stamp this city as the undisputed capital of Asia. Unsurprisingly, then, the Romans, eager to add to the graveyard of empires, and poised menacingly as they were just three hundred miles to the north-west, had always found it an irresistible target. A near-impregnable one as welclass="underline" for only once, back in 283, had a Roman emperor actually succeeded in capturing the city from the Sasanians, and even then he had promptly been struck by lightning, certain proof of the indignation of Ohrmazd. Nor was it only the heavens that stood guard over Ctesiphon. Beyond the vast ring of walls encircling the city, there stretched the immensity of the irrigation system: moat after endless moat. Back in 363, during the course of the final Roman attempt to capture Ctesiphon, even mosquitoes had been summoned to the city’s defence: great clouds of them, in the wake of the deliberate cutting of the dykes by the Persians, had shadowed Julian’s approach, so that “by day the light of the sun, and by night the glitter of the stars, were blotted out.”66