Stephen IX was a Benedictine monk and abbot of Monte Cassino who served as pope from 1057 until 1058. Born Frederick into the Ardenne-Verdun family of the Duchy of Lorraine, he began his religious career as a canon in Liège. He rose to prominence as a chancellor under Pope Leo IX, participating in a critical embassy to Constantinople that preceded the East–West Schism. After a period of seeking refuge at Monte Cassino, he was elected to the papacy, where he worked to uphold the Gregorian Reform and manage conflicts with the Normans.