To find the most expensive single item ever acquired by the Library of Congress, you're going to need a map. The library announced the purchase yesterday of the Waldseemuller world map of 1507, a cartographic treasure and the first known document to call a land mass "America." The old and rare chart is also the first to depict two oceans instead of one.

The price was $10 million.

John Hebert, chief of the library's geography and map division, said, "I am anxious to get it up on display and to get people together to really study this piece. Not only what's on the map, but where it came from."

The library purchased the 41/2-by-8-foot chart, drawn in France by German mapmaker Martin Waldseemuller and his associates, from Prince Johannes Waldburg-Wolfegg of Germany. The whole thing took awhile. After making a down payment in June 2001, the library set out to raise enough money to seal the deal. Congress paid $5 million. The rest was received from private donors, including Discovery Communications, Philadelphia investor Gerald Lenfest, New York industrialist David Koch and a number of others.

Originally, the prince hoped to sell the library other documents -- another world map and three globe coverings -- along with the Waldseemuller map for $14 million. All of the maps are bound together, and have been in the possession of the library during the negotiations. "We still have the hope that the entire portfolio of materials will stay here," Hebert said.

James H. Billington, librarian of Congress, said in a statement, "The map, giving our hemisphere its name for the first time, will be the keystone of the library's unparalleled collection of maps and atlases." The library has a vast and variegated collection of maps and atlases from around the globe -- some dating back to the 1300s.

The purchase of the Waldseemuller map, Billington said, "marks the culmination of an effort that has extended over many decades to bring this unique historical document to America where it can be on display in the nation's library for all to see."

For 350 years the Waldseemuller map was tucked away in a 16th-century castle and considered lost. In 1901 it was rediscovered. In the mid-1980s, the map was exhibited at the National Museum of Natural History. "It's a very important map both for the history of cartography and for the history of this hemisphere," said Helena Wright, the museum's curator of graphic arts.

The library describes the map as being in pristine condition.

Under the terms of the contract, the map will be displayed in the library's Thomas Jefferson Building. A special exhibition space is being created. The library plans to invite a host of high-ranking German and American officials to a formal celebration in 2004, but the map will be unveiled to the America public in the upcoming exhibition "Rivers, Edens, Empires: Lewis & Clark and the Revealing of America," which opens on July 24.

The Library of Congress purchased cartographer Martin Waldseemuller's 1507 world map for $10 million.