The Walt Disney Co. donated one of the world's most significant private collections of African artwork yesterday to the Smithsonian's National Museum of African Art.

The gift of 525 objects includes 15th-century carvings, rare ivory figures and evocative brass masks. It was assembled over 20 years by the late Paul Tishman, of the influential New York real estate family. The lot was sold to Disney in 1984 and, except for a few small shows, it has been kept in a humidity-controlled warehouse in California.

"This is a transforming gift to the Museum of African Art," Smithsonian Secretary Lawrence M. Small said at a news conference yesterday.

Although the African Art Museum has almost 8,000 objects, the Disney art is important because of the high quality of the works, according to Smithsonian officials, who say that the Tishmans bought the best available African art for two decades.

The donation enhances the museum's leadership in the field, said Sharon F. Patton, director of the museum, which is on the Mall, mostly underground behind the Smithsonian Castle. "This gift is a 180-degree turn for us. It gives us a luxury and strength we have never had before."

For example, thanks to the new arrivals, the museum could easily mount an exhibition built around various styles of animal skin masks, including some from the existing collection and a wood and antelope-skin headdress -- an unusual 20th-century piece from the Calabar region of Nigeria -- that is part of the Tishman collection. In addition, the museum can now organize traveling shows without depleting its own holdings.

The works embrace an aesthetic of beauty, utility and spirituality. A wood crest mask made by the Bamileke people of Cameroon in the late 19th century is marked with geometric shapes and circular patterns used to show the rank of the king and other dignitaries. Another piece is an 18th-century bronze helmet mask with a story about the spiritual power of the king. Snakes and crocodiles illustrate how to destroy enemies.

There is an ivory hunting horn, one of three surviving examples of the work of a single artisan who lived in Sierra Leone during the 1490s. An early 19th-century ivory statue from Benin depicts a woman with decorations carved on her body wearing an elaborate necklace. She was probably an attendant to royalty, and holds money in her right hand.

"They are powerful documents and aesthetic statements," said Christine Mullen Kreamer, a museum curator.

Disney CEO Michael D. Eisner explained that over the years company officials wondered what to do "with this fantastic collection." Eisner said 50 organizations had asked about it, but finally, he decided, "there is only one National Museum of African Art. There is only one Smithsonian."

The precise value of the Disney-Tishman collection is hard to determine, and Smithsonian officials hesitate to put a dollar value on art that has not been on the market for more than 20 years. "It's probably between $20 million to $50 million. The market and value for African art has taken off," Patton said. Eisner said the collection "was of significant value, but not outrageous."

Selected works will be displayed immediately, and a show built around the collection is scheduled for February 2007 in a space to be called the Walt Disney-Tishman African Art Collection.

The collection holds a unique standing in the art world for several reasons. Its size sets it apart, as does the fact that the work was kept intact by the Tishmans and Disney. It reflects the discerning eyes of Tishman and his wife, Ruth. The couple were interested not only in African culture but also how masks from Gabon and the Democratic Republic of the Congo might have influenced artists such as Picasso.

When 150 works from the collection were exhibited at the Metropolitan Museum of Art in 1981, the show became a catalyst for research in the burgeoning field of African studies.

Disney bought the collection for display at its Epcot park near Orlando. Some of the collection was also shown at the National Geographic Museum at Explorers Hall in 2001. And selections have been displayed at the Louvre in Paris and the African Art Museum itself. Eisner said yesterday that Tishman, who died in 1996 at age 96, wanted the collection to stay whole to protect its worth, and now Disney is ensuring that by transferring it to the Smithsonian.

The Tishman collection's influence extended to Disney's animators. Eisner said yesterday that the Disney artists studied some of the objects to create images for "The Lion King." Because there are few, if any, private collections of its scope and caliber, the Tishman works have had many suitors over the years.

"I got several calls from Jacques Chirac, who wanted certain pieces for the Louvre," Eisner recalled. After these calls from the French president, Eisner decided that the Smithsonian was the proper venue. Small "had called about 25 times," Eisner said. After years of overtures from the Smithsonian, the transfer began to take final shape six weeks ago, Eisner said.

For the African Art Museum, which became a part of the Smithsonian 26 years ago (the Mall museum opened in 1987), the acquisition expands its archives and deepens its offerings.

"This gift represents the largest, most diverse collection of African art given to an American museum in a quarter-century," Patton said. At least 60 works from the collection will always be on display.

A mask of wood and antelope skin represents a hairstyle worn by girls who have become old enough to marry.

A mask from Benin is decorated with snakes and crocodiles, referring to the dangerous spiritual forces controlled by the king.