They also said other copies had been made, but there was no proof until, in 2009, the British Museum discovered they had parts of another copy.
McGregor says one of the cuneiform curators "read a small tablet" one day, and later that night he realized that he'd read some of the same words before -- on the Cyrus Cylinder. Excited, he called the cuneiform specialist curator to say he thought he'd found a copy.
Looking at it, the specialist said he thought he recognized the cuneiform "handwriting" of the ancient scribe. He "went off into other drawers and found another fragment of the same tablet."
The real bonus? The tablet had lines that were missing from the original cylinder.
The Cyrus Cylinder will travel from Washington to museums in Houston, New York, San Francisco and Los Angeles.
Want to go?
WHAT: "The Cyrus Cylinder and Ancient Persia: A New Beginning"
WHEN: Through April 28
WHERE: Arthur M. Sackler Gallery, 1050 Independence Ave. SW, Washington, DC 20560
CONTACT: 202-633-1000; www.asia.si.edu