 Marx married Jenny von Westphalen (1814–1881), his childhood sweetheart, in June 1843. They would spend their lives together and have seven children, of whom just three daughters—Jenny (1844–1883), Laura (1845–1911), and Eleanor (1855–1898)—survived to adulthood. Marx is also widely thought to have fathered a child—Frederick Demuth (1851–1929)—with Helene Demuth (1820–1890), housekeeper and friend of the Marx family.