In nomine Domini

In nomine Domini (Latin: In the name of the Lord) is a papal bull written by Pope Nicholas II and a canon of the Council of Rome. The bull was issued on 13 April 1059 and caused major reforms in the system of papal election, most notably establishing the cardinal-bishops as the sole electors of the pope, with the consent of minor clergy.

Until the publication of the bull, the election of the pope was often decided by a puppet electoral process. The Holy Roman Emperor often directly named a deceased pope’s replacement, or the pontiff named his own successor. Such a nomination under the canon law was not a valid election and the legal electors would have to ratify the choice, though undoubtedly they would naturally be swayed by circumstances to give effect to the imperial preference.

In the 1050s, Cardinal Hildebrand (the future Pope Gregory VII) began to challenge the Holy Roman Emperor's right of approbation. The predecessor of Nicholas II, Stephen IX, had been elected during a period of confusion following the death of Emperor Henry III and, twelve months later, the death of Pope Victor II, whom Henry III had installed as pope. Stephen IX's election had obtained the consent of the empress-regent, Agnes of Poitou, despite the omission of the traditional preliminaries and the waiting of the cardinals for the imperial nomination.

Soon after his appointment as pope in 1058, upon the death of Stephen IX, Nicholas II called a synod at Sutri, with imperial endorsement provided by presence of an imperial chancellor. The first task of the synod was to denounce and excommunicate the irregularly elected Antipope Benedict X, who was a puppet of the powerful Count of Tusculum and presently in Rome.

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