Leo IX shine sunan Paparoma Katolika wanda ya yi aiki daga Fabrairu 12, 1049, har zuwa mutuwarsa a ranar 19 ga Afrilu, 1054. A cikin mahallin ƙamus, kalmar "Leo IX" yawanci tana nufin wannan adadi na tarihi. maimakon kalma mai takamaiman ma'ana.
