 He was the second of four sons (there were also ten daughters) born to Julius Delius (1822–1901) and his wife Elise Pauline, "née" Krönig (1838–1929).Delius's parents were born in Bielefeld, Westphalia, and Julius's family had already lived for several generations in German lands near the Rhine but was originally Dutch.Julius's father, Ernst Friedrich Delius, had served under Blücher in the Napoleonic Wars.