Mary, who was known as Minnie, was born on December 12, 1850, at
Powel House, her family home in
Philadelphia, Pennsylvania. She was the daughter of William Henry Rawle (1823–1889) and Mary Binney (
née Cadwalader) Rawle (1829–1861), both from prominent old Philadelphia families, the Rawles and the Cadwaladers. She had one younger brother, who died young of
diphtheria was a prominent attorney in Philadelphia with
Rawle & Henderson, a firm founded by her great-grandfather in 1783. When she was eighteen years old, her father remarried to Emily Cadwalader, the daughter of
Thomas McCall Cadwalader, her mother's cousin and Mary's own cousin twice removed. Her paternal grandparents were William Rawle Jr. and Mary Anna (née Tilghman) Rawle, the granddaughter of Chief Justice
Benjamin Chew. Her great-grandfather was
William Rawle, the
U.S. District Attorney in
Pennsylvania who was a founder, and first president, of the
Historical Society of Pennsylvania, a president of the
Pennsylvania Abolition Society, and a
trustee of the
University of Pennsylvania for 40 years. Her mother was the eldest daughter of
John Cadwalader, a
U.S. Representative and
Federal Judge, and his first wife, Mary (née Binney) Cadwalader, a daughter of
Horace Binney, also a U.S. Representative who was known for his public speeches as well as the founding of the
Hasty Pudding Club at
Harvard. ==Society life==