HIS GRACE the Duke of Devonshire would certainly say no were you to visit Chatsworth, his august country house, to ask if you might borrow his Raphaels and Rembrandts, his rare books and his gems, his furniture and silver, and his Leonardo, too.

But he said yes to Washington's Annemarie H. Pope.

Were you to go to Britain's oldest art museum to ask for master drawings, for Guardis, Canalettos, Fragonards and Turners, your request would be denied. The Ashmoleum at Oxford does not lend its treasures lightly.

But the Ashmoleum is lending many of its finest 18th-century master drawings to the International Exhibitions Foundation of Annemarie H. Pope.

She controls no grand collection, no government employs her, yet in the Principality of Pictures she holds ambassadorial rank.

Her offices on H Street are far from grandiose. Typewriters clack there, and telephones ring. In Washington she seems an ordinary businesswoman with five young assistants, a cluttered desk, a job. But she has another life. She often sups in palaces, millionaires accept her, the governments of Europe grant her decorations. Though she is barely known to the public that she serves, those who rule the most exalted regions of the art world lend her treasures gladly. Few great museums anywhere have arranged as many touring exhibitions as Annemarie H. Pope -- more than 1,000 separate showings of 100 different shows.

Recently she privately approached the Baron Thyssen-Bornemisza, who lives in a villa at Lugano, Switzerland, and there collects Old Masters. "Except for the Royal Collection inherited by the queen of England," writes John Walker, the director emeritus of the National Gallery of Art, "the Thyssen-Bornemisza Collection is now the greatest private collection in the world." The baron is the owner of admirable pictures by Rembrandt, Rubens, Fragonard, Ducci and El Greco, Zurbaran and Goya; these and 50 more, all drawn from his collections, will begin a U.S. tour here on Nov. 18 at the National Gallery of Art.

The museums did not borrow these works of art directly; the baron, instead, chose -- as had kings and dukes before him -- to lend his precious pictures to the private and non-profit Washington foundation of Annemarie H. Pope. When asked how she obtained the baron's exhibition, she answers, "through a friend."

Of course, there are other Washingtonians and part-time Washingtonians -- the National Gallery's Carter Brown, the government's Peter Solmssen of Dr. armand hammer, the close friend of the Soviets -- who also play important roles in bringing to this country international exhibits. But they represent the government, or fortunes, or great institutions. Pope, a private citizen, does it on her own.

"We do not have, and do not want, a ministry of culture," says Solmssen, a photographer and painter and former foreign service officer who is now the International Communications Agency's adviser on the arts. It is not his job to stamp his taste on international exchanges; instead he expedites, he aides. "I improve the flow," he says, "and in both directions." When other nations want to show their treasures in America, they often contact Solmssen; when Thomas Hoving -- then director of the Metropolitan Museums of Art -- went to Cairo to negotiate the Tut show, Solmssen went along. Before our government indemnifies visiting exhibitions, the ICA must certify that the show in question is in the nation's interest.

Governments these days, for reasons of diplomacy, often send each other objects. We recognize Peking and are soon lent Chinese bronzes; we do the same for East Berlin and are shown Dresden's treasures; Sadat speaks to Nixon and the Tut show starts its tour. "Art exchanges," Solmssen says, "are good for good relations. Some regard the process as a form of propaganda, but I cannot accept that. If we learn to understand the Chinese people better, everyone is helped. And the trade-offs here are few. Such touring shows don't hurt. They cost a little money, but that's about it."

The Arts and Artifacts Indemnity Program, a sort of governmental insurance program approved by our Congress, was specifically designed to promote such exhibitions. Politicans like them, and the National Endowments encourage them as well by helping pay their bills.

But there remains another region of the art world where governments play minor roles, where private forces rule, where the oldest and most delicate protocols apply. Manners and connections there count for more than cash. And when independent aristocrats and millionaires, people used to privacy, privilege and power, choose to lend America the treasures they control, they often do so through the offices of Annemarie H. Pope.

She conceives, packages and sells her traveling exhibits. "First I pick the subject, then I choose the objects, then I try to find a curator or scholar to act as guest director. When selected, they take over. The writing of the catalogue -- and of course the final choices -- are not mine, but theirs.

"While they are doing their jobs, my staff and I are busy here at work on schedules and budgets, on all the details involved. We generally speak first to the National Gallery. I spoke to Carter recently and offered him, quite literally, eight separate exhibits. The Chicago Art Institute is particularly interested, as am I, in Old Master drawings. Boston in very good for Oriental art, and so, too, is Seattle. Once we have an exhibition and a schedule of showings, then we go after the cash."

Many museum visitors have seen her exhibitions, though they might not have known it: Museums, rather greedily, tend to take the credit for the packaged shows they buy. The National Gallery's first major African art show, the Hirshhorn's recent showing of David Hockney's graphics, the National Portrait Gallery's showing of American self-portraits, the Phillips Collection's display of John Clarence Laughlin's photographs, the Corcoran's retrospective of Milton Avery's prints, the Virginia Museum's Chatsworth show, the Baltimore Museum's Ashmoleum exhibit -- all these shows were hers.

She is probably near 70, but declines to state her age. She is disciplined and dignified; her manners are impeccable, her posture is erect. Meeting her one thinks of steel wrapped in velvet. "I'd hate to meet her in an alley," says one former employee.

Her life has been a blend of scholarship and socializing, privilege and labor. To those who know her slightly, her frequent trips to Europe, her regular grand tours, seem luxurious and delightful. But when traveling abroad she works: "You cannot just march in to some grand country house and say, 'I'll take this and this and this.' You must be far more sensitive." In making exhibitions the busy-work is endless. There are loan forms to fill out, budgets to be drafted, insurance to be purchased, catalogs to edit, letters, letters, letters, schedules to meet.

In person, one senses that she has had to match every gracious weekend at a resort or palace with as many tedious hours at her telephone or desk. It is true she married well -- her husband, John A. Pope, once served as director of the Smithsonian Institution's Freer Gallery of Art -- but she did not inherit, neither did she buy, her present high position in the Principality of Pictures.

Her ambassadorial credentials, although wholly unoffical, were already in high order when 13 years ago her newly established International Exhibitions Foundation organized its first Washington exhibit. "Chinese Art From the Collection of His Majesty King Gustaf VI Adolf the King of Sweden" began its U.S. tour here at the National Gallery of Art. But she had begun accumulating her knowledge -- and connections -- more than 30 years before.

She was born in Dortmund, Germany, and received her Ph.D. from the University of Heidelberg in 1932. The next year she was introduced to the highest levels of the art world of America through the legendary "museum course" that Paul Sachs taught at Harvard.

"Things were different then," she says. "In those days, great collectors did not share their art through public exhibitions. They bought their pictures for themselves, but they showed them to Paul Sachs. Even now, at Chatsworth, there are no master drawings on view for the public. All the fine things there are kept in the duke's private quarters, or in the library in boxes. The same was true in New York in the 1930's. The Widener Collection in Philadelphia, the Bache, the Kress, the Altman were not yet in museums, but they were open to Paul Sachs. And he showed them to his students. With Paul Sachs, you saw everything." She saw, and her career was under way.

In 1944, after working for two years at the Portland Art Museums, she began arranging traveling shows for the then-new American Federation of Arts. In American today there are three national organizations supplying major traveling exhibits to American museums -- the AFA, the Smithsonian Institution's Traveling Exhibition Service (SITES) and the International Exhibitions Foundation. Those three programs prosper still -- in part because Pope organized all three.

At the AFA she worked for Robert Woods Bliss, the owner of Dumbarton Oaks; between 1951 and 1964, while at the Smithsonian, she worked beneath the broad umbrella of the U.S. government. In 1965 she set out on her own.

"I had worked there long enough," she says, but it is not clear why she left. It was whispered at the time that S. Dillon Ripley, the new Smithsonian Secretary, asked her to -- that he was displeased by the way she ran her office, and by the close attention she had begun to pay to the semi-independent National Gallery of Art.

The Gallery in those days gave little staff and little cash to temporary shows. Pope, for many years, worked closely with John Walker -- organizing exhibitions of the sort that the Gallery is now guite capable of arranging for itself. "for many years," says Carter Brown, the Gallery's director, "we thought Mrs. Pope an adopted member of the staff." What she did for the museums once, she does for many more today.

"When I started in this business," she says, "the participating museums paid all the bills themselves. Since then we've developed other funding sources. When the government agrees to indemnify a show, we are saved insurance, the largest item in the budget." Since that program started in 1976, the government has indemnified more than $773 million worth of traveling art at a saving to museums of $7 million in insurance premiums. There is a $250 million limit to the total value of the foreign works the government protects at any given minute, but so many shows are touring now that that quarter-billion-dollar ceiling already has been reached. The crash of a cargo plane could cost taxpayers plenty, but the United States, so far, has had to pay no claims.

"The Endowments, too," says Pope, "have been extremely generous. So have IBM and SCM and other corporations. And the Andrew W. Mellon Foundation has given us a grant so that we may maintain the quality of our catalogues."

Not so many years ago, before the days of jets, government insurance, the National Endowments and large curatorial staffs, museums had to rely on Pope and her few peers for a regular supply of traveling exhibits. Today they often organize their loan shows by themselves. "But I do not think," she says, "that they will put us out of business. They will always need more exhibitions than they can arrange themselves. And our shows will not go begging if their quality is high."