Pope John II (born Mercurius) was pope from 533 to 535.

He was the son of a certain Projectus, born in Rome and a priest of the Basilica di San Clemente on the Caelian Hill. He was made pope on 2 January 533. The basilica of St. Clement still retains several memorials of "Johannes surnamed Mercurius". Presbyter Mercurius is found on a fragment of an ancient ciborium, and several of the marble slabs which enclose the schola cantorum bear upon them, in the style of the sixth century, the monogram of Johannes.

He was the first pope to adopt a new name (regnal name) upon elevation to the papacy, as his theophoric birth name honoured the Roman god Mercury.

At this period simony (the purchase or sale of church offices or preferment) in the election of popes and bishops was rife among clergy and laity. During the sede vacante of over two months, "shameless trafficking in sacred things was indulged in. Even sacred vessels were exposed for sale". The matter had been brought before the Senate, and laid before the Arian Ostrogothic Court at Ravenna. The last decree (Senatus consultum) which the Roman Senate is known to have issued, passed under Boniface II, was directed against simony in papal elections. The decree was confirmed by Athalaric, king of the Ostrogoths. He ordered it to be engraved on marble and to be placed in the atrium of St. Peter's Basilica in 533. By one of Athalaric's own additions to the decree, it was decided that if a disputed election was carried before the Gothic officials of Ravenna by the Roman clergy and people, three thousand solidi would have to be paid into court. This sum was to be given to the poor. John remained on good terms with Athalaric, who, being of the Arian Christianity, was content to refer to John's tribunal all actions brought against the Roman clergy.

John III Sobieski (Polish: Jan III Sobieski, Lithuanian: Jonas Sobieskis) (17 August 1629 – 17 June 1696) was one of the most notable monarchs of the Polish–Lithuanian Commonwealth, from 1674 until his death King of Poland and Grand Duke of Lithuania. Sobieski's 22-year-reign was marked by a period of the Commonwealth's stabilization, much needed after the turmoil of the Deluge and Khmelnytsky Uprising. Popular among his subjects, he was an able military commander, most famous for the victory over the Turks in the 1683 Battle of Vienna. Following his victories over the Ottoman Empire, he was called by the Turks the "Lion of Lechistan" and held as the saviour of European Christendom by the pope.

John Sobieski was born 1629 in Olesko, a small town near Lwów in Poland (now Lviv, Ukraine) to a notable noble family de Sobieszyn Sobieski of Clan Janina. His father, Jakub Sobieski, was the Palatine of Ruthenia and Castellan of Kraków; his mother, Zofia Teofillia Daniłowicz was a granddaughter of Hetman Stanisław Żółkiewski. After graduating from the Nowodworski College in Kraków, young John Sobieski then graduated from the philosophical faculty of the Jagiellonian University. After finishing his studies, together with his brother Marek Sobieski, John left for western Europe, where he spent more than two years travelling. During that time he met major political figures: Louis II de Bourbon, Charles II of England and William II, Prince of Orange, and learnt French, German and Italian, in addition to Latin. This proved to be vital during his later military career.

Blessed Pope John Paul II (Latin: Ioannes Paulus PP. II, Italian: Giovanni Paolo II, Polish: Jan Paweł II), born Karol Józef Wojtyła (Polish: [ˈkarɔl ˈjuzɛf vɔjˈtɨwa]; 18 May 1920, Wadowice, Republic of Poland – 2 April 2005, Apostolic Palace, Vatican City), reigned as Pope of the Catholic Church from 1978 until his death in 2005. He was the second-longest serving Pope in history and the first non-Italian since 1523.

John Paul II was acclaimed as one of the most influential leaders of the 20th century. He was instrumental in ending communism in his native Poland and eventually all of Europe. John Paul II significantly improved the Catholic Church's relations with Judaism, Islam, the Eastern Orthodox Church, and the Anglican Communion. Though criticised by progressives for upholding the Church's teachings against artificial contraception and the ordination of women, and by traditionalists for his support of the Church's Second Vatican Council and its reform, he was also widely praised for his firm, orthodox Catholic stances.

Pope John Paul I (Latin: Ioannes Paulus PP. I, Italian: Giovanni Paolo I), born Albino Luciani (17 October 1912 – 28 September 1978), reigned as Pope of the Catholic Church and as Sovereign of Vatican City from 26 August 1978 until his death 33 days later. His reign is among the shortest in papal history, resulting in the most recent Year of Three Popes. John Paul I was the first Pope to be born in the 20th century and the last Pope to die in it.

In Italy he is remembered with the appellatives of "Il Papa del Sorriso" (The Smiling Pope) and "Il Sorriso di Dio" (The smile of God).Time magazine and other publications referred to him as The September Pope.

Albino Luciani was born on October 17, 1912 in Forno di Canale (now Canale d'Agordo) in Belluno, a province of the Veneto region in Northern Italy. He was the son of Giovanni Luciani (1872?–1952), a bricklayer, and Bortola Tancon (1879?–1948). Albino was followed by two brothers, Federico (1915–1916) and Edoardo (1917–2008), and a sister, Antonia (1920–2009).