Pope Stephen IX was the Bishop of Rome and ruler of the Papal States from 3 August 1057 to his death on 29 March 1058. He was a member of the Ardenne-Verdun family, who ruled the Duchy of Lorraine, and started his ecclesiastical career as a canon in Liège. He was invited to Rome by Pope Leo IX, who made him chancellor in 1051 and one of three legates to Constantinople in 1054. The failure of their negotiations with Patriarch Michael I Cerularius of Constantinople and Archbishop Leo of Ohrid led to the permanent East–West Schism. He continued as chancellor to the next pope, Victor II, and was elected abbot of the Benedictine monastery of Montecassino.
Patriarch Michael enthroned, Madrid Skylitzes
Emperor Henry III and Empress Agnes kneeling before the Virgin Mary, Speyer Evangeliary
Pope Victor in the Pontifical of Gundekar
Stephen IX on a 19th-century religious card
Michael I Cerularius or Keroularios was the patriarch of Constantinople from 1043 to 1059 AD. His disputes with Pope Leo IX over church practices in the 11th century played a role in the events that led to the Great Schism in 1054.
The enthronement of Michael I Cerularius, from the Madrid Skylitzes
Lead seal of Michael Cerularius as Patriarch of Constantinople
