Emperor Leo may refer to: Leo I (emperor) (401–474), Byzantine emperor and Eastern Orthodox saint Leo II (emperor) (467–474), Byzantine emperor Leontius (?-706), Byzantine emperor under the regnal name of Leo Leo III the Isaurian (c. 685–741), Byzantine emperor Leo IV the Khazar (750–780), Byzantine emperor Leo V the Armenian (775–820), Byzantine emperor Leo VI the Wise (866–912), Byzantine emperor