Editing Pope Stephen IX (section)

{{Use dmy dates|date=August 2023}}
{{Short description|Head of the Catholic Church from 1057 to 1058}}
{{Redirect|Stephen IX|the Moldavian ruler|Ștefan IX Tomșa}}
{{Pope Stephen ToP Dab|IX}}
{{Infobox Christian leader
| type = Pope
| honorific-prefix = [[List of Popes|Pope]]
| name = Stephen IX
| image = 
| title = [[Bishop of Rome]]
| church = [[Catholic Church]]
| birth_name = Frederick of Lorraine
| term_start = 3 August 1057
| term_end = 29 March 1058
| predecessor = [[Pope Victor II|Victor II]]
| successor = [[Pope Nicholas II|Nicholas II]]
| birth_date = {{circa|1020}}
| birth_place = [[Duchy of Lorraine|Lorraine]], Holy Roman Empire
| death_date = 29 March 1058 (aged 37–38)
| death_place = [[Florence]], [[March of Tuscany]], Holy Roman Empire
| other = Stephen
}}

'''Pope Stephen IX''' ({{langx|la|Stephanus}}, christened '''Frederick'''; {{circa|1020}}<ref>{{cite book|first=Karl|last=Mittermaier|title=Die deutschen Päpste. Benedikt XVI. und seine deutschen Vorgänger|year=2006|pages=102}}</ref>&nbsp;– 29 March 1058) 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 (priest)|canon]] in [[Liège]]. He was invited to [[Rome]] by [[Pope Leo&nbsp;IX]], who made him [[papal chancellor|chancellor]] in 1051 and one of three [[papal legate|legates]] to [[Constantinople]] in 1054. The failure of their negotiations with Patriarch [[Michael&nbsp;I Cerularius]] of Constantinople and Archbishop [[Leo of Ohrid]] led to the permanent [[East–West Schism]]. He continued as chancellor to the next [[pope]], [[Pope Victor II|Victor&nbsp;II]], and was elected abbot of the [[Benedictine]] monastery of [[Montecassino]].

Stephen was [[papal selection before 1059|elected]] to succeed Victor on 2 August 1057. As pope, Stephen retained the Montecassino abbacy, enforced the [[Gregorian Reform]], and continued Leo&nbsp;IX's efforts to expel [[Normans from southern Italy]]. He died in [[Florence]], apparently poisoned by Romans, while endeavouring to crown his brother [[Godfrey the Bearded]] as [[Holy Roman emperor]]. He remains the most recent pope to take the [[pontifical name]] "Stephen".