From the Thornton Wilder Society Website

Thornton Wilder’s oldest sister Charlotte Wilder (1898-1980) was a poet who shared the Shelley Memorial Award for Poetry in 1937 with Ben Belitt. She attended high schools in Berkeley, California, and in China, and graduated from Berkeley High School. She received an M.A. degree from Radcliffe, and went on to a teaching career at Wheaton College and Smith College. In 1934, Charlotte moved to New York to devote all her time to writing. In 1941, she suffered a severe nervous breakdown. With the exception of periods in the early 1950s, she remained in institutions the rest of her life.