The pivotal Persian ruler Darius I (550–486 B.C.) came to power at age 28 and quickly proved himself a great military leader and an even greater administrator. His ascension to king of the Persian Empire was cloaked in intrigue. It’s thought he may have staged a coup to claim the throne. Some Persians viewed Darius as a usurper, and many subjects in distant lands saw the succession crisis as an opportunity to rebel.
As a result, Darius spent his first three years quelling uprisings. With his elite imperial guard, known as the Ten Thousand Immortals, he commandingly restored order to the realm and expanded its scope. He advanced its eastern frontier to the Indus River and its western boundary beyond the Bosporus, the strait separating Asia from Europe.
More significant than his conquests, though, were the measures he took to consolidate his vast dominion. Darius demonstrated an organizational genius rivaled by few ancient or modern rulers. He divided the empire into some 20 provinces (called satrapy), governed by appointed local officials (satraps) with minimal interference from their Persian overlords. He set the amount of annual tax due from each province and sent agents to watch his distant satraps and ensure they weren’t overtaxing their subjects. Those “eyes and ears of the king” kept sedition to a minimum.
Both taxation and trade were facilitated by coins Darius issued, a practice he adopted from Lydian and Greek rulers. Unlike gold or silver ingots that had to be weighed to determine their value, Persian coins—depicting Darius as a warrior—had uniform values and were easily exchanged.
He improved on an irrigation system that was in place during Cyrus’s reign, stimulating a significant expansion of agriculture and settlement throughout the empire’s parched landscape. Irrigation tunnels called qanats moved water from underground sources at high elevations, and bridges resembling the Roman aqueducts that would follow centuries later carried the water to distant villages.
Traders, troops, and imperial spies moved smoothly on roads built by Darius (and maintained by his successors). The greatest of those was the Royal Road, which stretched more than 1,500 miles, from Ephesus on the Aegean Sea to Susa in western Iran, the empire’s administrative center. Other roads led south from Susa to Pasargadae, Cyrus’s former stronghold and burial place, and to Persepolis, where Darius and his heirs built a splendid palace complex. Caravans of traders riding donkeys or camels took about three months to traverse the Royal Road, but royal dispatches could be relayed from Susa to Ephesus in a week by a network of 111 courier stations set at equal intervals along it.
A Persian identity
Under Darius’s rule, Zoroastrianism became the state religion, providing a cohesive sense of identity across his far-flung empire. Yet Darius did not impose the belief system on those of other faiths. His subjects in conquered lands could continue to worship their own gods and keep their own cultural traditions.
All of these measures helped Darius stimulate trade and productivity. Accordingly, the standard of living in Persia rose, and Persian dominance in the Near East became entrenched. Darius I ruled for more than three decades. He lost battles against the Greeks (including the famous battle of Marathon) in the years leading up to his death in 486 B.C. But Persia would exist as a political entity for more than a thousand years, and many old Persian traditions endure to this day.
This text is an excerpt from the National Geographic special issue The Most Influential Figures of Ancient History.