Patrick Hayes, who worked tirelessly for years to make Washington a musical town of the first rank, was honored last night at the Kennedy Center. He was celebrated as a hero of the age of Art Militant in America, a man who not only loved the performing arts but believed passionately that they could change this town, and this country, for the better.

Hayes, who died last year at the age of 89, was honored by musicians and friends--the former inevitably became the latter--with whom he had long or important relationships. The concert, presented by the Washington Performing Arts Society--an organization Hayes founded and guided for decades--filled the Concert Hall with the sounds of small, all-in-the-family musicmaking.

It was a light evening, more celebratory than nostalgic, and the musicians (an impressive roster including Leonard Slatkin, James Galway, Andre Watts, Roberta Peters, Evelyn Lear, Thomas Stewart and Leon Fleisher) seemed animated by the legendary impresario's equally legendary sense of humor. They laughed and ribbed each other, and engaged the audience casually as if the event were happening in a gracious, oversize living room.

Hayes began his career in musical Washington in 1941, when he was appointed manager of the National Symphony Orchestra. In 1947 he began working as an independent impresario, bringing to the city the great artists of one of the greatest ages of music. Almost two decades later, he began the nonprofit Washington Performing Arts Society.

But it was Hayes's commitment to building a diverse and open audience that defined him. He was a man of vision and of mottoes, one of which still trips off the tongues of those he worked with: "Everybody in, nobody out."

It was a belief that led him, in 1953, to present the incomparable African American contralto Marian Anderson at DAR Constitution Hall. It was an important symbolic effort to redress the debacle of 1939, when the Daughters of the American Revolution refused to let Anderson sing there.

Last night soprano Leontyne Price made a surprise appearance to sing the spirituals beloved by Hayes. And, in dual tribute to the strong Irish affiliations of this New York City-born music lover, the concert ended with a musical benediction: a traditional old Irish blessing that transformed itself into a gospel number with an Irish heart, sung by a mixed choir.

Each of the evening's musicians and speakers brought out a different aspect of the man. Pianists Watts and Fleisher performed the playful and insouciant Schubert Rondo in D, Op. 138 (D. 608), for piano four hands. It reminded one of a comment by former congressman James Symington in 1989, that Hayes "put the 'imp' in impresario."

NSO Music Director Slatkin performed with his wife, soprano Linda Hohenfeld, and James and Jeanne Galway joined them, swapping partners for a string of soprano, flute and piano numbers. It was true chamber music in the best spirit of give and take. Perhaps Hayes would have enjoyed the bonhomie of it all.

Vocalists Evelyn Lear and Thomas Stewart (whom Hayes presented in their first duo recital in the early 1970s) told the audience of his attentiveness to nervous and insecure performers, and the power of his charisma, which he could telegraph to artists from the wings of a concert hall.

"His understanding of the frailty of artists was legendary," Stewart said.

Lear remarked that it was not an evening to mourn, and indeed it wasn't. Hayes accomplished his dreamed-of immortality project--to establish an organization that would carry on his mission. The Washington Performing Arts Society is that organization, and it shows all signs of rude good health.

Hayes's life spanned an era of great opportunity and promise for the arts, a sleepy cottage industry in Washington before Hayes went to work. By the end of his life, America was indisputably the equal of Europe in the export of great music and dance, and Washington had leapt forward to genuine artistic cosmopolitanism.

Throughout the evening, Hayes was honored as a man who had exceptional standards, an exceptional ear and a natural-born impresario's ability to insist on the best without ruffling a single feather. If last night's concert was, rightly, celebratory, the morning brings with it the challenge Hayes set by example. He made Washington an important stop on the touring schedules of many of the world's greatest artists. Now Washington has to continue the difficult work of living up to its cosmopolitan reputation, and always insisting on the best.

CAPTION: Andre Watts, left, and Leon Fleisher at last night's tribute to Patrick Hayes.