At a time when Iran’s identity in the West is being defined by portrayals of revolution in the movie “Argo” and by the nation’s nuclear program, an exhibit opening this week at the Arthur M. Sackler Gallery recalls a time when the ancient kingdom of Persia was a test bed for tolerance and human rights.

The show, opening Saturday, marks the first U.S. appearance of one of the most celebrated objects from antiquity: the Cyrus Cylinder, a football-shaped relic inscribed with orders issued by King Cyrus the Great after his conquest of Babylon in 539 B.C., credited by Hebrew scripture for repatriating exiled Jews and allowing them to return to Jerusalem.

The decrees helped usher in the Achaemenid, or First Persian Empire, the largest in the ancient world, which covered parts of three continents, including portions of current-day Greece and much of the Middle East and central Asia. The dynasty brought such innovations as a postal system, a network of roads and a professional army and civil service before collapsing sometime around 330 B.C.

But scholars say the most enduring contribution might have been Cyrus’ directives to restore temples and grant freedom of worship to peoples who had been displaced by the Babylonians he defeated — a gesture exhibit curators say inspired leaders from Alexander the Great to Thomas Jefferson. (Jefferson owned two copies of the “Cyropaedia,” a flattering biography of the ruler that portrays both his virtue and skills as a politician.)

The cylinder “may not be the first declaration of its kind, but it’s the most famously referred to and the most internationally recognized early human rights charter in the world,” said Pardis Minuchehr, director of the Persian program at George Washington University. “It has a message that resonates over the centuries and is very inspirational.”

“One of the goals of this exhibition is to encourage us to reflect that relations between Persians and Jews have not always been marked with the discord that disfigures the political map of the Near East today,” said Julian Raby, director of the Sackler Gallery and Freer Gallery of Art, the Smithsonian’s museums of Asian art. He noted the Bible refers to Cyrus as “the anointed” of the Lord and that philosophers for thousands of years viewed the king as the model of a virtuous ruler.

The exhibit, “The Cyrus Cylinder and Ancient Persia,” also features architectural fragments, carvings and plaques showing the spread of the Zoroastrian religion, and luxury objects such as bracelets and gold and silver bowls. The show is in D.C. through April 28 and will travel to Houston, New York, San Francisco and Los Angeles.

The Cyrus Cylinder was unearthed in southern Iraq in 1879 by a team from the British Museum, where it’s been displayed and studied for more than 130 years. Beyond validating the biblical version of events, it has been a source of cultural detente in recent times. Throngs reportedly viewed the original when it was on display in the National Museum of Iran in Tehran in 2010. Both the shah and Iran’s President Mahmoud Ahmadinejad tried to appropriate the cylinder’s message to fit their priorities.

The relic shows how politically savvy kings in the ancient world took power. By promptly announcing reforms, they at once legitimized conquest, publicly rebuked the vanquished regime and portrayed a new ruler as benevolent and acting in concert with the gods. That was especially important for Cyrus, who presided over as many as 50 million people — about 44 percent of the world’s population.

The inscription, in Babylonian cuneiform, provides Cyrus’ account of his conquest of Babylon, which he claims to have achieved with the help of the god Marduk. It goes on to enumerate relief measures he brought to the city and explains how he returned a number of images of gods seized by the Babylonian King Nabonidus to their temples throughout Mesopotamia. Though Jews are not specifically referenced, their return to Palestine following their deportation by Nebuchadnezzar II was part of Cyrus’ policy, according to scholars.

Some contemporary historians believe Cyrus was less a human rights champion than a hard-nosed pragmatist, realizing he couldn’t possibly set up a powerful central government to preside over such a vast kingdom. Regardless, his policies provide a window into a time of dramatic change in the ancient world.

“You could almost say the Cyrus Cylinder is a history of the Middle East in one object,” said Neil MacGregor, director of the British Museum. “It is a link to a past which we all share and to a key moment in history that has shaped the world around us.”