Sarah Lathrop was the wife of Erhardt Brown and the mother of Emmett L. Brown. Her last name was the source of his middle name, Lathrop.
Sarah grew up in Hill Valley with the rest of her family, the Lathrops, during the 1880s. She had a brother named Abraham and owned a ragdoll named Emma.
In 1931, her husband considered her as stubborn as Emmett, while Emmett described her as "gentle and sweet and endlessly patient."
Her husband died prior to 1968 while she herself had seemingly died by 1985.