From BiblePortal Wikipedia

People's Dictionary of the Bible [1]

Sergius Paulus ( Ser'Ji-Ŭs Pau'Lus ), proconsul of Cyprus.  Acts 13:7, etc. a.d. 44. He is described as an intelligent man, and yielded to the claims of the gospel.

Cyclopedia of Biblical, Theological and Ecclesiastical Literature [2]

the name of several Roman Catholic pontiffs.

I, pope from 687 to 701, contemporary with the Venerable Bede, was born at Antioch and reared at Palermo. The most noteworthy event of his administration was a dispute with the Eastern Church, which ultimately led to the separation of the East from the West. The emperor Justinian II had convoked an ecumenical council ( Concilium Quinsextum ) at Constantinople, and legates were sent to attend it by Sergius, who signed its decrees; but, as six decrees had been passed which were contrary to the practice of Rome (e.g. omitting nearly all the Latin councils and papal decretals from the list of authentic sources of Church law, acknowledging the validity of the whole eighty-five canones apostolici, denouncing the celibacy of the clergy, prohibiting fasting on Saturdays during Quadragesima, making the patriarch of Constantinople equal to the pope, etc.), the pope forbade their promulgation. The emperor ordered the imprisonment of the refractory pope, but was himself dethroned after a revolt in his army. Rome continued to reject this council, and this occasioned the disputes which subsequently divided the Church. Sergius succeeded, on the other hand, in restoring the communion with Rome of the churches which had been alienated through the Controversy of the Three Chapters. The other prominent incidents of his pontificate were the founding of the bishopric of Utrecht by Willibrod, and the issuing of an ordinance by which the Agnus Dei was required to be sung three times before the communion in the service of the mass. Oct. 9 was set apart in commemoration of this pope.

II, pope from 844 to 847. He contributed materially to the exaltation of the papacy by daring to disregard the requirement of seeking the confirmation of his accession and consecration by the civil power, and by maintaining his position in the face of the protest raised by the emperor Lothaire against this infraction of the law of the realm. The controversy of Paschasius Radbertus respecting the Lord's supper was begun in the reign of this pope.

III, pope from 904 to 911, who owed his elevation to the influence of the shameless Theodora and her no less shameless daughters Marozia and Theodora, the actual rulers of the time in Rome. He was grossly immoral, and lived in licentious relations with Marozia, who bore him several children, among them the future pope John XI, though the latter statement is denied by many respectable authorities. The only noteworthy events of his pontificate were his approval of the fourth marriage of the emperor Leo Philosophus, which a subsequent synod at Constantinople (920) condemned, and the renewed introduction of the Benedictine rule at Clugny by the abbot Berno.

IV, pope from 1009 to 1012, previously bishop of Alba. With him began the custom that the popes should adopt a new name on assuming the tiara. The story has it that Sergius was formerly called Bocca Di Porco, i.e. swine's snout. Being ashamed of the name, he assumed that of Sergius, and thus introduced a custom which has been followed by all subsequent popes.