The Akkadian Empire (ca. 2340–2198 B.C.) represented something entirely new in human history: a dynasty that conquered and ruled over a vast territory, incorporating people of different ethnicities who were forced to adopt its ways. At its height, the empire encompassed much of modern Iraq and parts of Syria, though its heartland is believed to have been the fertile plains of central Mesopotamia watered by the Tigris and Euphrates Rivers. Among other innovations, the empire’s founder, Sargon (reigned ca. 2340–2285 B.C.), instituted Ishtar, the Semitic goddess of war, as the patron deity of the dynasty, rather than of just a single city. A landmark of the Akkadian capital, Agade, was the Eulmash temple, dedicated to Ishtar. The Akkadians also pioneered new forms of art and writing, and their economic reach—including trade with the far-off Indus Valley—brought exotic goods and animals such as elephants, monkeys, and crocodiles to the capital. “Everywhere you looked, there was something new,” says Assyriologist Benjamin Foster of Yale University.

Long after their empire fell, Akkadian rulers were seen as models by Mesopotamian dynasties such as the Assyrians and Babylonians. “Their relics were admired, their inscriptions were studied, and their historical memory was kept alive for two thousand years,” says Foster. Agade was largely abandoned, although its location was well known as late as the time of the Babylonian king Nabonidus (reigned 555–539 B.C.), who claimed to have excavated the Eulmash temple’s ruins. “I relaid the foundation, the altar, and dais, along with two ziggurats, and made firm its brickwork,” Nabonidus writes. “I built them up to ground level so that the foundation of Eulmash shall never again be forgotten.” Over time, though, the Eulmash temple, Agade, and the Akkadians themselves were, indeed, all forgotten. When Assyriologists rediscovered the cultures of ancient Mesopotamia in the mid-nineteenth century, they recognized Agade as the birthplace of an enduring style of political organization and took a keen interest in finding it. Yet, more than a century and a half later, the city remains lost.

Modern scholars believe the capital was located along the Tigris’ banks, roughly between the Iraqi cities of Baghdad and Samarra. However, the river has changed course over the millennia and may have washed away the remnants of Agade long ago. Nele Ziegler, an Assyriologist at the French National Center for Scientific Research, says that trying to determine Agade’s location involves a great deal of guesswork. “We don’t have many clues to where it is,” she says. “There’s no text that tells you, for instance, how much time it took to go from Sippar to Agade.” Ziegler is partial to a location near the confluence of the Adhaim and Tigris Rivers, around 50 miles north of Baghdad, in part based on an eighteenth-century B.C. text that describes a convoy traveling from the city of Eshnunna to the Kingdom of Mari. Along the way, the group stopped in Agade to drink beer, and a musician named Hushutum was kidnapped. Eshnunna is known to lie just east of Baghdad, and Mari is in far eastern Syria, so scholars can roughly estimate where Agade might have been. “We’d really like to find it,” says Ziegler. “There was a cultural revolution going on when the Akkadians came to power. It would be really interesting to see what they imagined as their ideal capital city.”