Did Ludwig Mies van der Rohe really design the Barcelona chair, the most famous seat of the 20th century?

Or does his mistress, Lilly Reich, deserve much of the credit for the Barcelona chair and a number of other classic modern furniture designs attributed for the last half century to the Bauhaus Miester?

Reich's importance to the designs is revealed by Ludwig Glaesar, curator of the Mies van der Rohe Archive at a new show of the furniture just opened at the Museum of Modern Art her.

To the design world, the impact is similar to what would happen if the Louvre director announced he believed Leonardo da Vinci's lover helped paint the Mona Lisa.

The truth of the story may remain forever hidden, obscured by wartime separations, and losses, discreet and ladylike silences, a love affair complicated by a business partnership, professional courtesie's and the overpowering Mies myth. But enough remains to make a story bound to have an effect on anyone who ever bought a $1,628 Mies chair or ever sat in one.

Glaeser made his points in an interview and in the catalog of the show, not yet published. For the exhibit, Glaeser gathered extensive oral histories and a study of the furniture drawings. Glaeser's evidence:

All the famous furniture was designed during the years Mies and Reich lived and worked together, the mid-20s to the late '30s.

Testimony of former employees and clients of Mies/Reich who told of her extensive role.

The fact that Mies assigned one patent on an important cantilever device to her.

Her extensive training in furniture design with Josef Hoffman, the Wiener Werkstatten master who was a pioner of modern design.

The two, who had only their profession in common, came together through a designers' organization in the 1920s.

Miles was self-educated, the son of a stone mason. He learned architecture as an apprentice. Relch was the sophisticated daughter of well-to-do cactory owners. She was well-traveled, a student of the best design schools of her day and was widely admired for her "unfailing" taste combined with rigorous standards."

In 1927, they collaborated on a glass industries display at the Weissenhof Exhibition, where they each had model rooms as well. This was the beginning of their lives and work together.

"It is certainly more than a coincidence that his involvement in furniture and exhibition design began in the same year as his personal relationship with Lilly Reich," Glaeser said.

Georgia van der Rohe, the architect's daughter (who is making a movie based on filmed interviews with her father) said at the Miles exhibit opening, "My father didn't live with us. My mother was not well. I suppose you might say she was fragile. She died youg. We children and sort of a retinue of governesses and such, lived in various places in Europe, while she took 'cures.' We would just see him once or twice a year."

Glaeser explains how Mies and Reich worked: "Extremely articulate, she participated in the actual work through conversation, and while Mies did much of his thinking by sketching - consuming stacks of typewriter copy paper - Lilly Reich seems to have had her ideas already in her head.

"Miles, according to one of his employees from these years, rarely solicited anybody's comments but was always eager to hear her opinion. Even without any temporal distance, the nature of such collaboration makes it nearly impossible to sort out ideas and hands."

Their most productive year, 1928, saw the beginning of the Tugendhat house in Brno, Czechoslovakia, one of the most important of modern houses, and the designs for the Barcelona pavilion for the German government. Mies and Reich were hired to design an industrial exhibit for the exposition. Then at the last minute, they were also asked to produce a paviolion to serve as a setting for the Spanish king to sign her name in a gold book.

The two Barcelona chairs, chrome steel with an "X" frame, one side rising to form a back, had leather-covered, foam-rubber cushions, an innovative stuffing for the time. Although later Mies often spoke of designing the chairs on the back of an envelope he also once said he had a "graveyard" of rejected designs for them.

"Mies," Glaeser writes, "always cherished his privacy and had let only those who worked or studied with hime observe the creative process, making the world believe that the Barcelona chair had sprung from his head like Athena, in its final perfection."

Glaeser thinks that Reich probably was the one who decide on the kid leather, the soft stuffing, the buttons and tuftings of the Barcelona chair.

"We know from a letter that she was also responsible for the much-admired continuous cane weaving of the 1927 side chairs. The roll and pleat upholstery shows up first in one of her 1931 jobs."

She is also credited by Glaeser with the combination of the metal legs with wood tops, as in the desk for Philip Johnson in 1930.

During these years, Glaeser said, Reich's "energetic and enterprising nature also benefitted Mies's office although she never ceased to maintain her own. She continued to take care of his business and personal affairs after he left for Chicago in 1938, and she visted him there at the outbreak of the war.

"It is not certain whether she had hopes of joining him and teaching at the Illinois Institute of Technology as she had taught under Mies at the Bauhaus.

"Lilly Reich survived the war but did not live long enough to see Mies again; she died at the age of 62 in Berglin in 1947."

Glaeser suggests that Reich gave Mies some financial support. The furniture designs anyway were his principal income during the German years when he was unable to get large architecture commissions.

Mies furniture designs are sill manufactured by Knoll International which is adding eight pieces to the line. The designs are also widely imitated in cheaper versions.

Reich gave the majority of the Mies archives to architect Eduard Ludwig for safekeeping. Glaeser worked with Ludwig in Berlin and through him came to know of Reich's great influence.

So the question remains, if Reich was so good, why wasn't she famour?

For one thing, she slayed in Germany during the war. Mies came to the United States, designed the Illinois Institute of Technology and the Lakeshore Apartments in Chicago (also the Martin Luther King Library in Washington). She died shortly after World War II, without having a chance to reestablish herself. He lived on until 1969.

The other part of the answer has to do chance to reestablish herself. He lived with the position of women in Germany of that period. And, perhaps, the reluctance of a woman of that day to demand credit from a colleague who was also a lover.

Mies, according to Glaeser, was not "a man suited to marriage. I always think I have found the last of the mistresses, and then another turns up. But I have been told that the most recent was only jealous of Lilly Reich."