Lying in the middle of a plain in modern day Iran is a forgotten ancient city: Persepolis. Built 2,500 years ago, it was known in its day as the richest city under the sun. Persepolis was the capital of Achaemenid Persian Empire, the largest empire the world had ever seen, but after its destruction, it was largely forgotten for nearly 2,000 years, and the lives and achievements of those who built it were almost entirely erased from history. Alexander the Great’s troops razed the city to the ground in a drunken riot to celebrate the conquest of the capital, after which time and sand buried it for centuries.

It was not until the excavations of the 1930s that many of the relics, reliefs, and clay tablets that offer so much information about Persian life could be studied for the first time. Through archaeological remains, ancient texts, and work by a new generation of historians, a picture can today be built of this remarkable civilization and their capital city. Although the city had been destroyed, the legacy of the Persians survived, even as they mostly remain an enigma to the West and are not nearly as well understood as the Greeks, Romans, or Egyptians. In a sense, the Achaemenid Persian Empire holds some of the most enduring mysteries of ancient civilization.

When considering this empire’s rulers, the two most often referenced are Xerxes, the leader of the Persian invasion of Greece which caused the heroic sacrifice of the Spartans and their allies at Thermopylae, or Cyrus the Great, the man who created the Persian Empire. But the Persians had another critical ruler sandwiched between them, and Cyrus’ accomplishments and Xerxes’ defeats would not have been possible without him. That king was Xerxes’ own father, Darius I, best known as Darius the Great.

Darius I took the throne after the death of Cyrus’ son, Cambyses II, and though his reign would not have been possible without the construction of the empire and the administrative groundwork laid by Cyrus the Great before him, Darius proved himself just as worthy of the epithet. Reigning for over 35 years, Darius kept control of the massive Persian Empire despite numerous rebellions and uprisings, and he also managed to implement reforms and improvements that established the empire’s golden age. He followed the example of Cyrus before him in his foreign policy and mode of kingship as well, offering tolerance and patience to various cultures and religions, and even treating his enemies fairly in most cases.

Perhaps his ultimate success can be seen most clearly in the passage of power at the end of his life. By that time, his reign had been long and stable, and though he died of illness somewhat unexpectedly, his kingdom was still so firmly established that the kingship passed to his son Xerxes without any question or upheaval. Under Darius the Great’s rule, the empire reached its greatest extent, stretching from the Indus Valley and Central Asia in the east to Libya and the Danube River in the west.

Not surprisingly, the majority of surviving sources regarding the Persian rulers are the product of Greek writers, so it was inevitable that Darius has been depicted in unflattering terms for thousands of years. The details of his invasion of Greece cast him as the villain in the dramatic Greek retelling of the Greco-Persian Wars. As usual, the truth lies far more towards the middle. A few individuals have undertaken to explore the true complexities of his character, and through these works and a few ancient sources, most particularly Herodotus, a more accurate picture can be derived, even if the bias of Greek accounts still colors the information. In reality, very little objective information exists as to the personality and character of the king.