The office of the Pope is called the papacy. His ecclesiastical jurisdiction is often called the "Holy See" (Sancta Sedes in Latin), or the "Apostolic See" based upon the Church tradition that the Apostles St. Peter and St. Paul were martyred in Rome.
A its inception, the pope was elected by a body of clergymen. The Sacred College of Cardinals, which dates to the 9th Century, became the entity primarily responsible for selecting the pope.
While the office was not temporal at its founding, it did gain substantial temporal powers through the course of history, peaking in the Middle Ages. In recent centuries, the papacy's temporal powers have been considerably reduced.
This article lists the known popes found in the works of Harry Turtledove after the Point of Divergence. Many popes who served before the POD of a given alternate history are mentioned in passing. Also stories set in OTL may reference past popes, or even the sitting pope; these references should not be listed here unless they are the focus of a particular story, and/or are connected to speculative elements.
In the seventh century AD, Emperor Constans II succeeded in regaining Italia from the Lombards. He installed his own Bishop of Rome since he disapproved of the doctrines of the incumbent. That individual fled to the Franco-Saxon kingdoms. The monarchs at Constantinople remained in control of Rome and took care that all subsequent Popes would be subservient politically to the Throne and theologically to the Patriarch of Constantinople. The exiled Pope started his own rival line, under the Franco-Saxon protection, whose authority was also accepted by the Anglelanders who were politically opposed to the Franco-Saxons, and was also accepted (secretly) by some people under the Imperial rule. Thus, there was created a permanent situation of two rival Popes. Generation after generation, each of the competing Popes strongly condemned his rival as a heretic, but neither had the power to end the schism. It was still like that nearly 700 years later, at the time of Basil Argyros, and likely to go on indefinitely.
The Papacy was a religious institution which survived the Soviet Union's victory in the Cold War. It was implicitly understood by all that the Soviet government didn't want to risk the anger of staunchly Catholic populations in countries such as the Italian People's Republic.
After the Great Black Deaths wiped out 80% of the population of Europe, the papacy was forever changed. As the plague ran for decades, the reigning pope was horrified by the arrival of a religious leader named Henri, who preached patience and modesty, with the promise of a better world. When he was proclaimed the Second Son of God, the sitting Pope, then headquartered in Avignon, colluded with the King of France in ordering Henri's torture and execution on the wheel. The next day, both the Pope and the King went to church to give thanks for Henri's death. In a freak accident, the church collapsed, killing both men. Shortly thereafter, the Great Black Deaths ran its course, validating Henri in the eyes of his followers. The death of the pope was seen as a miracle, and the New Revelation and the Final Testament quickly overran Catholicism in what little remained of Christendom.
By the 21st century AD, the Papacy had little political power, but its spiritual authority was seen as just barely enough to keep extremist groups such as the Aquinists in check. In 2018, Pope Marcellus IX issued a set of bulls urging international cooperation and tolerance of progressive movements. Conservative extremists simply disregarded Marcellus' pronouncements, regarding him as an Antipope. The civilized nations of the world knew the importance of keeping a reasonable and relatively liberal man in St. Peter's seat, and made sure to preserve the safety of Marcellus and like-minded men, knowing how easily the situation could worsen.
Each and every pope since St. Peter was fed upon by Jesus, who was transformed into a vampire shortly after he was crucified. This practice was kept secret from the world, and was known only by the reigning pope and the Order of the Pipistrelle, which was responsible for maintaining the practice.
At least one pope, Honorius I, became a vampire himself as a result of this practice. Pope John Paul I did not turn into one, but his health never recovered, and he died not long after ascending to the papacy.
Several OTL Popes up to the early 8th century are referenced in the historical novel Justinian. Since the story is told from the perspective of the Eastern Orthodox ruler Justinian II of the Byzantine Empire, the papacy is not presented in a favorable light.
The following Popes reigned during or after the points of divergence of various stories.
In Worldwar, Pius XII is the incumbent Pope at the POD, and is later killed in January 1944 during the Race Invasion of Tosev 3. While the papacy is referenced in Colonization, the reigning popes go unnamed.
Pius XII is also the reigning pope in The Hot War: Fallout, whose POD comes in 1950. He is also referenced in The War That Came Early: Coup d'Etat and Settling Accounts: The Grapple (the only Pope referenced in Southern Victory). The latter two series have a POD prior to his accession, so Pius XII may be someone other than Eugenio Pacelli in either series.