De-accessioning — the process of museums selling off art from their collections — is always controversial. But rarely does a community get as exercised as residents of Buffalo are over the decision by the board of the Albright-Knox Art Gallery to sell almost 200 antiquities and classic works in order to purchase contemporary art.

The objects, which include works of African, Oceanic, and pre-Columbian art, Chinese ceramics and porcelain, classical sculpture and Old Master paintings, will be sold in a series of sales at Sotheby’s, beginning next month. The most valuable piece, a late Hellenistic/early Roman imperial bronze sculpture of Artemis and the stag, is expected to sell for between $5 million and $7 million. The total sale is estimated at $15 million, which will be added to the museum’s restricted endowment for acquisitions, which currently stands at between $19 million and $20 million. The museum’s overall endowment is $59 million.

The announcement of the board’s decision in early November provoked dozens of critical letters to the editor of the Buffalo News. In recent weeks, a group, headed by a Pulitzer Prize-winning poet, Carl Dennis, formed to try to block the sale.

The director of the Albright-Knox, Louis Grachos, has justified the decision to de-accession these works by saying that the museum’s core mission, reaffirmed in a strategic planning process completed in 2001, is to collect, exhibit, and preserve modern and contemporary art — not antiquities. “The first 36 acquisitions, from 1862 through the end of the 19th century, were all contemporary artworks,” Mr. Grachos said. When the museum opened its permanent home in 1905, the early exhibitions, including one of photography and another of German Expressionism, also reflected this mission, he said.

Through the years, he acknowledged, the museum has acquired older, historic materials through gifts and, in some cases, purchases by former directors. But, Mr. Grachos said: “We’ve never had designated curators devoted to any of these areas — to develop the collections or, frankly, to even organize exhibitions around them. As objects on their own, they are important, they’re beautiful, but they are clearly outside the main mission.”

Mr. Dennis said he was distressed that the board made the decision without informing or consulting the museum’s members. “There seemed a very deliberate attempt to keep it hidden from the community and from the members of the gallery,” he said. His group, called “Buffalo Art Keepers,” is considering two options: Under the museum’s rules, he said, if they can gather 5% of the membership of the museum, they can hold a meeting and vote on the de-accessioning. “Whether they have to accept the vote is still an open question,” he said. “It’s never been done before. But if they really want to be stubborn, we’ve had discussions with lawyers, too” about means of blocking the sale.

The works being sold, Mr. Dennis argued, provide needed context for visitors to understand the modern works in the collection. “There is no Metropolitan Museum here to give people a historical reference point,” he said. “They say, ‘Well, you can drive to Toronto.’ Well, it’s two hours away, and that’s all the difference between getting people interested in art and not. Educators send their students” to the Albright-Knox. “They’re not going to send them to Toronto.”

Mr. Dennis said he saw a “kind of corporate mentality” behind the de-accessioning. “The thinking is that they own a big conglomerate, and they’re selling off a subsidiary because it doesn’t give them any glamour.”

A professor of Greek art and archeology at the University of Buffalo, Livingston V. Watrous, said he did not object to the deaccessioning per se, but he said he was bothered that in recent years the museum has put much of its older works into storage. “They’ve taken virtually all of the antiquities off of the museum walls,” Mr. Watrous said. “They’ve also put a large segment of the 19th- and 20th-century holdings — and many of these are world-famous paintings — in the storerooms.”

Now, when he sends his students to the museum, “there’s virtually nothing there that is earlier than 1900,” he said. “Grachos has had no experience with museums. He’s treating this museum as if it were a gallery, and it’s not. He has a responsibility to the people of New York to display the permanent collection.”

Mr. Grachos disputed the suggestion that, under his tenure, more of the earlier works had been put in storage.

Mr. Grachos said the decision to de-accession — as opposed to pursuing other means of raising funds — reflected the realities of present-day Buffalo. “The population is declining; the economy is shrinking,” he said. “We do not have the kind of patronage that this community once had and we don’t have the economy to expect hundreds of thousands of visitors to support the institution.”

But pursuing the museum’s mission is even more important in that local context, Mr. Grachos said. “We are one of two or three legitimate world-class cultural attractions in this region,” he said. “This region is realizing that its assets are the Albright-Knox Art Gallery and the outstanding and historic architecture, from [Henry Hobson] Richardson, to [Louis] Sullivan, to Frank Lloyd Wright, to Eero Saarinen. The Albright-Knox is one of the key flagships for cultural tourism in western New York.”

Mr. Grachos said the museum has tried to communicate with people who wrote letters or made calls in opposition to the de-accessioning, as well as to arrange meetings with the groups “who have been more public and vocal.” But “our board of directors is unanimous in moving forward,” he said, “It’s without question a bold move, but we see it as a very prudent and important move for the future of the Albright-Knox.”