NASHVILLE, Tenn. (AP) _ Rose Williams, the sister of Tennessee Williams who often served as the late playwright's muse, has died of natural causes at the age of 87.

Miss Williams died Wednesday at Phelps Memorial Hospital in Tarrytown, N.Y., where she had been taken from a private nursing home in Ossining, said Janet Beard, director at Bethel Methodist Home.

In the late 1930s, when a young Tennessee Williams was away at college, his parents gave their consent for Rose to have a prefrontal lobotomy to cure a worsening case of schizophrenia.

The operation did not succeed, and Rose was institutionalized for the rest of her life. The tragedy stayed with Tennessee Williams until his death in 1983.

``Rose became something of a muse for him,'' said Wyatt Prunty, director of the Sewanee Writer's Conference. ``Shy and withdrawn as a young woman, she became the model for the sister in `The Glass Menagerie.'''

After Williams' success with `A Streetcar Named Desire,' he could afford to take her out of a state institution and give her better quality care, said Albert Delvin, an English professor at the University of Missouri in Columbia.

``What comes through is a real joy that he was able to break the routine of her delusional life. It gave an artistic order to his life. She became a central subject in his work,'' Delvin said.

Williams' will left his manuscripts to Harvard University and ordered that proceeds from his $10 million estate be used to support Rose.

Williams directed that the rest be spent to support aspiring writers at the University of the South at Sewanee, where his maternal grandfather studied theology in the late 1890s.

Her death means that the rights to Williams' plays and the remainder of his estate _ valued at $7 million _ will go to Sewanee, located 80 miles south of Nashville.

The University of the South has received more than $500,000 a year from the Williams estate for a fund that supports the Sewanee Writer's Conference, a summer writing retreat that has attracted Arthur Miller, William Styron, poet Howard Nemerov and other authors.