Karl Muller (1813-1894) published two standard works, Fragmenta Historicorum Graecorum and Geographi Graeci Minores, which have never been superseded, but very little is known about his life, and he is frequently confused with Carl Otfried Muller, another great German classicist of the nineteenth century. Born near Hannover, Karl and his brother and collaborator Theodor both studied at the University of Goettingen, but both left Germany in 1839, probably for political reasons. They moved to Paris, where the five-volume Fragmenta was produced in partnership with the printer-publisher Ambroise Firmin-Didot. It covers the works of historians which have been lost, but of which fragments survive in other works.