Elizabeth (August 31, 1844January 28, 1911) was born in Boston, Massachusetts to American Congregational minister Austin Phelps and Elizabeth Wooster Stuart Phelps (1815–1852). Her baptismal name was Mary Gray Phelps, after a close friend of her mother's. Her mother wrote the Kitty Brown series of books for girls under the pen name H. Trusta. Her brother, Moses Stuart Phelps, was born in 1849. Her mother was the eldest daughter of Moses Stuart, the eminent president of Andover Theological Seminary. Her mother was intermittentantly ill for most of her adult life and died of brain fever shortly after the birth of their third child, Amos, on November 20, 1852, Then eight years old, Mary Gray asked to be renamed in honor of her mother.