far as their scope, approach, and intention are concerned.
CHAPTER 1 Geography and Climate
D. T. Potts
Any attempt to describe the geography and climate of an empire faces a formidable challenge, for by definition such supra‐regional states were territorially vast and, in most cases, characterized by a wide range of physical features, ecosystems, and climates. The borders of the Achaemenid Empire transected what geographers have termed interior Asia, Europe, southwest Asia, and Africa (Brice 1966: Fig. 1). The empire included the entirety of the earlier Neo‐Assyrian Empire in addition to the Iranian plateau, a good portion of western Central Asia (as far east as Sogdia), the Indo‐Iranian borderlands, and parts of north Africa, including Libya to the west of Egypt and Kush (Nubia) to the south. Major bodies of water, including the Aegean, Mediterranean, Red, Black, Caspian, and Arabian Seas, the Persian Gulf, and the Gulf of Oman bounded the Achaemenid satrapies. Substantial mountain ranges, including the Taurus, Amanus, Lebanon, Anti‐Lebanon, Caucasus, Zagros, Kopet Dag, and Hindu Kush, constituted significant sources of timber and minerals, as well as impediments to travel, breaking up the empire into a series of basins, plateaus, and valleys connected by natural thoroughfares – seas, rivers, mountain passes, and tracks across plains and deserts.
The fundamental ecological “facts of life” did not change with the rise of the Achaemenids, of course. The Nile Valley was not suddenly more fertile, any more than the Mesopotamian plain was suddenly more saline than it had been. The cedars of Lebanon were no less abundant than they had been under the Assyrians, notwithstanding the fact that enormous quantities of timber had been harvested and sent to the Assyrian capitals; horses were no scarcer in Media than previously; bitumen no less abundant at Hit; and lapis lazuli was just as available in Afghanistan as ever. But the sheer size of the empire required an extraordinary effort to manage it effectively and no doubt tested the capabilities of the state administrative apparatus at the same time as it helped to build considerable managerial and logistical expertise. Efficient communication across enormous distances became a sine qua non of imperial success and demanded regular travel on a scale scarcely seen in any period of human history prior to the creation of the Achaemenid Empire.
Within the borders of the empire, the major mountain ranges are pierced by only half a dozen major passes and these have necessarily acted as conduits for travel across the millennia. Beginning in the east these are the Khyber pass, formed by the Kabul river as it flows through the mountains of Pakistan; the Bolan pass, which pierces the hills of southwestern Pakistan where the Nari river cuts through them; the Ardewan pass in the Hindu Kush, which opens up communication between Merv in Turkmenistan and Herat in western Afghanistan, thanks to the Kushk river; the Sefid Rud gap, which bursts through the Alburz mountains, giving access from the Caspian Sea to the Iranian plateau, near Rasht; the Zagros Gates, where the Diyala river cuts through the Zagros mountains near Bisitun, providing access from the Mesopotamian plain to the Iranian plateau in the east Tigridian region; and the Cilician Gates, where a branch of the Tarsus river pierces the Taurus mountains, providing access from the western Anatolian plateau to the Mediterranean (Brice 1966: p. 28). Other important passes include the Homs Gap or Syrian Gates, where the Orontes river has cut a gap linking the Mediterranean coast with the interior of Syria, dividing the an‐Nusayriyah mountains and Jebal Zawiyah, Lebanon and Anti‐Lebanon mountains; the Persian Gates, in the Mamasani region of western Fars, through which most east–west traffic has to pass between Mesopotamia and the southwest Iranian lowlands (Khuzestan) to the west and the highlands around Pasargadae and Persepolis to the east (Speck 2002); and the Kotal Dukhtar, the only pass that leads from Bushehr on the Persian Gulf northwards toward Shiraz and Persepolis (Potts 2009: p. 283). There were many more passes of local importance scattered across the Achaemenid Empire, but each of these major ones can be considered “active” before, during, and after the period in question.
If Achaemenid administrators and military commanders felt that a tyranny of distance operated within the empire, it was at least mediated by effective communications that facilitated the movement of private individuals (Waerzeggers 2010), couriers (Herrenschmidt 1993; Briant 1992), armies, and officials (Hallock 1969) on foot, camel, horse, donkey, cart, barge, and boat. For the most part, travel was undertaken along roads already in existence. These included major routes that had been traversed since prehistoric times, from southern Babylonia, up the Euphrates and Tigris, and across northern Mesopotamia, descending into Syria and the southern Levant (Hallo 1964: Fig. 6); routes leading up the Tigris from Assyria to the Anatolian heartland (Hallo 1964: Fig. 6; Nashef 1987; Barjamovic 2011: p. 34); routes leading from the Levant southward into Egypt (Gardiner 1920; Potts 1982; Figuera 2000); and routes leading from southern Babylonia eastward through the Zagros Gates, on to and across the Iranian plateau (Herzfeld 1907), bound for Central Asia. Local routes, already well‐trodden by the Bronze Age (e.g. Ur 2009), almost certainly continued to be used as well. Guides, fast couriers, and guard stations had been known since the Bronze Age (Barjamovic 2011: pp. 38–51) and it is unlikely that the basic modalities of travel were significantly different in the Achaemenid period. Indeed, judging by the extant literary testimonia, travel in the Achaemenid period was as efficient as it was at any time prior to the development of motorized transport.
Millions of years of erosion of the folded mountain chains throughout the Achaemenid Empire, supplemented by ongoing alluviation, resulted in the infilling of numerous plains and plateaus, and the creation of large salt basins like the Dasht‐e Lut and Dasht‐e Kavir in Iran. True deserts like the African Sahara or the Arabian Rub’ al‐Khali generally lay outside the bounds of the empire, except in Libya, but gravel plains are particularly prevalent in the eastern reaches of the Achaemenid Empire. Nor were these generally mediated by appreciable rainfall, though it is clear that precipitation varied enormously across the length and breadth of the region controlled by the Achaemenids. This is scarcely to be wondered at in an empire spanning so many degrees of latitude and longitude. From the Indo‐Iranian borderlands to Libya, and from the Caucasus to Oman, an enormous range of ecosystems existed within the borders of the Achaemenid Empire (Wilkinson 2003).
Generally speaking, the climate of most of the empire may be characterized as a drier, continental variant of the Mediterranean regime (Brice 1966: p. 36). Rainfall across most of the Achaemenid Empire fell in winter, the exceptions being in parts of Central Asia (Choresmia, Sogdiana), the Indo‐Iranian borderlands (Sattagydia, India), the Caucasus (Armenia), and Egypt, where summer rains, influenced in the southern districts by the monsoon, were the norm. Pockets of territory in central Anatolia, around Lakes Van and Urmia, the central Iranian plateau, Sistan, and Afghanistan received rain in both seasons (Brice 1966: Fig. 9). Just as it has been in recent times (Kouchoukos et al. 1998: p. 480), inter‐annual variability in precipitation was probably great. Hyper‐arid zones may have received only a few dozen millimeters of rainfall each year, while sub‐tropical areas like Gilan and Mazanderan received enough rainfall to enable double‐cropping (e.g. growing rice in summer and wheat/barley in winter). To cite just one extreme, modern example of inter‐annual variability, unusually heavy rainfall in 1968 saw the level of Lake Urmia rise by no less than 2 m. (Bottema 1986: p. 243). Fluctuations of this sort are generally not recorded in ancient sources, with the exception of the Babylonian astronomical diaries. In addition to containing observations on the height of the Euphrates (Slotsky 1997: pp. 88–98), these mention a wide range of meteorological phenomena, including rain showers, lightning, thunder, and tornados (e.g. Sachs and Hunger 1988: p. 71, no. 384) that characterized the Babylonian winter of 384 BCE.
With every type of environment from the sub‐tropical in the north to the semi‐arid steppe, arid desert, and humid coasts along the Persian Gulf and Arabian Sea in the south, Iran itself is a microcosm – if one can use such a term to describe an area three times the size of France – of the diverse range of ecosystems found across the empire. In the higher ranges of the Zagros mountains, where peaks in excess
