Constitutio Romana

The Constitutio Romana (or “Roman Constitution”) was drawn up between King Lothair I of Italy (818–55), co-emperor with his father, Louis the Pious, since 817, and Pope Eugene II (824–27) and confirmed on 11 November 824. At the time the election of Eugene was being challenged by Zinzinnus, the candidate of the Roman populace. Eugene agreed to several concessions to imperial power in central Italy in return for receiving the military and juridical support of Lothair. The Constitutio was divided into nine articles. It introduced the earliest known Papal Oath, which the Pope-elect was to give to an imperial legate before receiving consecration. It also restored the custom established by Pope Stephen III in 769 whereby both the laity and clergy of Rome would participate in Papal elections.

There has been some debate between modern scholars whether the Constitutio was a "dead letter" with little practical impact, or marked a stage of the road to imperial domination of the Papacy.