If you’d paid more attention in Babylonian cuneiform class, you could read
the Cyrus Cylinder — an early bill of rights established by Cyrus the Great, who
conquered Babylon in 539 B.C. and founded the Persian Empire.

To the ancient Greeks and Mesopotamians, the Persians were the neighbors from hell. There was an exception: Cyrus the Great, who launched the Persian Empire by conquering Babylon in 539 B.C. He was praised in the Bible’s book of Ezra and by the fourth-century B.C. Athenian historian Xenophon.

The reason for their enthusiasm can be read ­— if you can read Babylonian cuneiform — on the Cyrus Cylinder, on loan from the British Museum to the Arthur M. Sackler Gallery as part of “The Cyrus Cylinder and Ancient Persia: A New Beginning.” The football-sized, barrel-shaped, baked-clay piece bears a royal decree that established freedom of religion, and allowed Jews — who’d been taken to Babylon after King Nebuchadnezzar II destroyed Jerusalem — to return to their homeland and rebuild sacred sites.

The cylinder’s text is “a meditation on how you govern a diverse society,” says Neil MacGregor, director of the British Museum. MacGregor calls the show “a small exhibition about the greatest empire the world had ever seen.” The cylinder represented a new sort of political organization, one that encompassed multiple faiths, languages and ethnicities.

The cylinder was unearthed during a British Museum-sponsored expedition in 1879, providing the first corroboration of the decree as recounted in the book of Ezra.

The episode was never memorialized by the Persians. Unlike other bygone empires, MacGregor explains, “we have no view of their views, what they did or how they did it.”

In addition to the cylinder, the exhibit features historic gold and silver coins, bowls and jewelry from the period. There are also recently translated clay-tablet fragments that reproduce some of the cylinder’s text.

Also highlighted is something (slightly) more recent: one of Thomas Jefferson’s two copies of Xenophon’s book on Cyrus, an inspiration to 18th-century pro-democracy thinkers. At that time, MacGregor notes, “only the United States took up the Persian model” of religious pluralism.

The Cyrus Cylinder has been invoked to legitimize many regimes that are far from democratic, including the current government of Iran. Perhaps that’s one of the hazards of being ahead of its time.

“Everybody has claimed Cyrus,” MacGregor says. “Just as everyone has claimed the Magna Carta.” Mark Jenkins (For Express)

Arthur M. Sackler Gallery, 1050 Independence Ave. SW; through April 28, free; 202-633-4880. (Smithsonian)