THE YEAR WAS 1942. AGNES DE MILLE, already in her late 30s and desperate for a dance hit, was engaged in a crucial lest of wills, trying to teach a corps of classically trained European male dancers how to move as if they were riding broncos. De Mille prevailed and out of that fusion came Rodeo, arguably the first truly American ballet.

The triumph was typical of De Mille's career—little ever came easy to her—but by the time she died of a stroke in her Greenwich Village apartment last week at 88, she had long since established herself as one of the grandes dames of American dance. Her 60-year career ricocheted between ballet and Broadway, producing enduring works for American Ballet Theatre and boisterous dances for such great musicals as Oklahoma!

Agnes was born in 1905 into a prosperous New York theatrical family. Her father, William Churchill de Mille, was a Broadway playwright; her mother, Anna George de Mille, was deeply involved in the single-tax movement started by her father, Henry George. Agnes's uncle was Cecil B. DeMille, the renowned producer and director of Hollywood epics.

With the failure of one of his plays in 1912, William went on Cecil's payroll and moved his family to Hollywood. Agnes, by her own admission, grew up "spoiled, egocentric [and] wealthy"—and intent on studying at a local ballet school against the washes of her lather, to whom dance was akin to prostitution. Anna sided with Agnes and introduced her to such stars as ballerina Anna Pavlova and modem dancer Ruth St. Denis.

After graduating from UCLA, De Mille set out, on her own, to become a dancer. From 1932 to 1936 she lived with her mother in Europe (her parents had divorced when she was 19), looking for the break that never came. But these were years of intense learning, culminating in Rodeo, hailed for telling the comic tale of a bronco-busting cowgirl in classical style. (That year, 1942, she also married concert manager Walter Prude, who died in 1988. Their son, Jonathan, now a professor of history at Emory University, was born in 1946.)

Rodeo, it turned out, was also an audition of sorts for Rodgers and Hammerstein's 1943 smash Oklahoma! De Mille continued the collaboration twice more, for Carousel (1945) and Allegro (1947), and then worked with Lerner and Loewe on Brigadoon (1947) and Paint Your Wagon (1951). Thereafter she turned her dance-making attentions to ABT—and, increasingly, to writing, authoring 12 books of essays and memoirs, until a stroke paralyzed her right side in 1975.

Even that slowed her only temporarily. In 1981 she learned to write with her left hand and published a book about her travails; last year she published another, on modern-dance doyenne Martha Graham, at almost the same time that she completed a new dance for ABT. From one end of her career to the other, she mixed the high and the low, the classical and the popular, astonishing and irritating purists. "Ours is an up beat," she explained at ABT's 50th-anniversary gala in 1990. "It keeps pressing us to go farther, to include everything so that we can savor everything...so that we will miss nothing."