Sergius IV became the 142nd pope, succeeding John XVIII.

Pope Sergius IV was the bishop of Rome and nominal ruler of the Papal States from 31 July 1009 to his death. His temporal power was eclipsed by the patrician John Crescentius. Sergius IV may have called for the expulsion of Muslims from the Holy Land, but this is disputed. Since his time, the practice that the person who has been elected to the office of pope takes on a new name became a tradition.

This chronological list of the popes of the Catholic Church corresponds to that given in the Annuario Pontificio under the heading "I Sommi Pontefici Romani", excluding those that are explicitly indicated as antipopes. Published every year by the Roman Curia, the Annuario Pontificio no longer identifies popes by regnal number, stating that it is impossible to decide which pope represented the legitimate succession at various times. The 2001 edition of the Annuario Pontificio introduced "almost 200 corrections to its existing biographies of the popes, from St Peter to John Paul II". The corrections concerned dates, especially in the first two centuries, birthplaces and the family name of one pope.

Pope John XVIII was the bishop of Rome and nominal ruler of the Papal States from January 1004 to his abdication in July 1009. He wielded little temporal power, ruling during the struggle between John Crescentius and Emperor Henry II for the control of Rome.