In February 1493, Christopher Columbus described his historic journey of the previous year in a letter to the king and queen of Spain. Though the letter was reprinted and circulated throughout Europe, only about 80 copies remain—and now the US is sending one of them, a stolen one, back to Europe, reports the Los Angeles Times.

The US Immigration and Customs Enforcement says the $1.1 million "Plannck II" copy donated to the Library of Congress in 2004 was being delivered to Italy after an investigation found it was stolen from Florence's Riccardiana Library and replaced with a high-quality photocopy decades ago, per the Local and Delaware News Journal.

After a researcher finally detected the forgery in 2012, authorities received a tip that the real one was in Washington. New tests have revealed that to be true.

Among other things, researchers detected bleach on the Library of Congress' copy, suggesting that the Riccardiana Library's stamp was once there but had been removed. It isn't clear when the letter was stolen from the museum, but officials say a Swiss collector somehow obtained it and sold it to an American in 1990.

It was then purchased at a New York auction in 1992 before that owner donated it to the Library of Congress in 2004. "It is interesting how 500 years after the letter was written it has made the same trip back and forth from America," says Italy's culture minister, per NBC News.

(Don't blame Columbus for syphilis.)

This article originally appeared on Newser: After Decades-Old Theft, 1493 Columbus Letter Is Returned