Hassam was known to all as "Childe" (pronounced like "child"), a name taken from an uncle. Hassam was born in the family home on Olney Street on Meeting House Hill in the Dorchester neighborhood of Boston, on October 17, 1859. His father, Frederick Fitch Hassam (1825–1880), was a moderately successful cutlery businessman with a large collection of art and antiques. He descended from a long line of New Englanders. His mother, Rosa Delia Hawthorne (1832–1880), a native of Maine, shared an ancestor with American novelist Nathaniel Hawthorne. His father claimed descent from a seventeenth-century English immigrant whose name, Horsham, had been corrupted over time to Hassam. With his dark complexion and heavily lidded eyes, many took Childe Hassam to be of Middle Eastern descent—speculation which he enjoyed stoking. In the mid-1880s, he took to painting an crescent moon (which eventually degenerated into only a slash) next to his signature, and he adopted the nickname "Muley" (from the Arabic "Mawla", Lord or Master), invoking Muley Abul Hassan, a fifteenth-century ruler of Granada whose life was fictionalized in Washington Irving's novel "Tales of the Alhambra".