Pope Alexander III in the context of "Thomas Becket"

Béla III (Hungarian: III. Béla, Croatian: Bela III., Slovak: Belo III.; c. 1148 – 23 April 1196) was King of Hungary and Croatia between 1172 and 1196. He was the second son of King Géza II and Géza's wife, Euphrosyne of Kiev. Around 1161, Géza granted Béla a duchy, which included Croatia, central Dalmatia and possibly Sirmium. In accordance with a peace treaty between his elder brother, Stephen III, who succeeded their father in 1162, and the Byzantine Emperor Manuel I Komnenos, Béla moved to Constantinople in 1163. He was renamed to Alexios, and the emperor granted him the newly created senior court title of despotes. He was betrothed to the Emperor's daughter, Maria. Béla's patrimony caused armed conflicts between the Byzantine Empire and the Kingdom of Hungary between 1164 and 1167, because Stephen III attempted to hinder the Byzantines from taking control of Croatia, Dalmatia and Sirmium. Béla-Alexios, who was designated as Emperor Manuel's heir in 1165, took part in three Byzantine campaigns against Hungary. His betrothal to the emperor's daughter was dissolved after her brother, Alexios, was born in 1169. The emperor deprived Béla of his high title, granting him the inferior rank of kaisar.

Stephen III died on 4 March 1172, and Béla decided to return to Hungary. Before his departure, he pledged that he would never make war against the Byzantine Empire. Although the Hungarian prelates and lords unanimously proclaimed Béla king, Lucas, Archbishop of Esztergom opposed his coronation because of Béla's alleged simony. Finally, the Archbishop of Kalocsa crowned him king on 18 January 1173, with Pope Alexander III's approval. Béla fought with his younger brother, Géza, whom he held in captivity for more than a decade. Taking advantage of the internal conflicts in the Byzantine Empire after Emperor Manuel's death, Béla reoccupied Croatia, Dalmatia and Sirmium between 1180 and 1181. He occupied the Principality of Halych in 1188, but it was lost within two years.

Manifestis Probatum (Latin for 'Manifestly proven') is a papal bull and the founding document of Portugal. On 23 May 1179 Pope Alexander III promulgated the bull. The bull officially recognized the independence of Portugal from Leon by confirming the Kingdom of Portugal to the now-recognized king Afonso Henriques and his successors. The bull is, therefore, the single most important written document from Portugal's independence process.

The Papacy did not recognize the legitimacy of Afonso's adoption of the royal title in 1139, and continued to regard him as a vassal of the kingdom of León. On December 13, 1143, Afonso wrote Pope Innocent II the letter Claves Regni (Latin for 'Keys of the Kingdom'), declaring his decision to enfeoff Portugal to the Holy See and asking for protection against any interference in Portugal's territory. On May 1, 1144, Pope Lucius II replied by letter Devotionen Tuam (Latin for 'Your Devotion') and stated that he recognized Afonso's devotion, but still referred to Portugal as a land instead of a kingdom, and to Afonso as duke instead of a king.

The Northern Crusades or Baltic Crusades were military campaigns undertaken by Catholic Christian military orders and kingdoms in an effort to Christianize the pagan Baltic, Finnic, and West Slavic peoples around the southern and eastern shores of the Baltic Sea. In some cases, such as with the Wendish Crusade, the campaign was partly motivated to control the rich resources found in the lands.

The most notable of these campaigns were the Livonian and Prussian Crusades. Some of these wars were explicitly regarded, during the Middle Ages, as crusades; for example, the military venture against the Estonians—and the "other pagans in those parts"—authorized by Pope Alexander III's 1171 crusade bull, Non parum animus noster. However, others—such as the (possibly mythical) 12th-century First Swedish Crusade and several subsequent incursions, undertaken by Scandinavian Christians against the then-pagan Finns—were dubbed "crusades" only in the 19th century, by romantic nationalist historians.

Lucas (Hungarian: Lukács; c. 1120 – 1181), also known as Luke, was a Hungarian prelate and diplomat in the 12th century. He was Bishop of Eger between 1156 and 1158, and Archbishop of Esztergom from 1158 until his death in 1181.

Lucas is believed to have come from a wealthy and influential family, but sources are uncertain of his origin. He was one of the first students of the University of Paris. When he returned to Hungary, his ecclesiastical career ascended quickly into the highest dignities. As a confidant of Géza II in his last years, Lucas had a significant impact on the country's foreign policy and diplomatic processes. Lucas was a staunch supporter of Stephen III during the struggles in the Árpád dynasty following Géza II's death, where Stephen III's reign was contested by his two uncles. The archbishop opposed both the intervention efforts of the Byzantine Empire and the Holy Roman Empire. Lucas had an ambivalent relationship with Stephen's brother and successor Béla III. The strict and uncompromising nature of his extremist Gregorianism challenged and weakened his partnership and alliance with the Holy See in the last decade of his archiepiscopal tenure, which coincided with the pontificate of Pope Alexander III.

Laudabiliter was a bull issued in 1155 by Pope Adrian IV, the only Englishman to have served in that office. Existence of the bull has been disputed by scholars over the centuries; no copy is extant but scholars cite the many references to it as early as the 13th century to support the validity of its existence. The bull grants the right to the Angevin King Henry II of England to invade and govern Ireland and to enforce the Gregorian Reforms on the semi-autonomous Christian Church in Ireland. Richard de Clare ("Strongbow") and the other leaders of the Anglo-Norman invasion of Ireland (1169–1171) claimed that Laudabiliter authorised the invasion. These Cambro-Norman knights were retained by Diarmait Mac Murchada, the deposed King of Leinster, as an ally in his fight with the High King of Ireland, Ruaidrí Ua Conchobair.

Successive kings of England, from Henry II (1171) until Henry VIII (1542), used the title Lord of Ireland and claimed that it had been conferred by Adrian's successor, Pope Alexander III (c. 1100/1105 – 1181).

The Order of Calatrava (Spanish: Orden de Calatrava) is one of the four Spanish military orders and the first military order founded in Castile, but the second to receive papal approval. The papal bull confirming the Order of Calatrava was given by Pope Alexander III on September 26, 1164. Most of the political and military power of the order had dissipated by the end of the 15th century, but the last dissolution of the order's property did not occur until 1838.

Non parum animus noster (Latin for "Our mind is deeply [troubled]") was a crusading bull issued by Pope Alexander III on either 11 September 1171 or 1172 to promote the Northern Crusades against the pagan Estonians and Finns. It was addressed to the rulers and peoples of Denmark, Sweden and Norway and begins with a description of the threat posed by the Estonians. Alexander declared:

Alexander further promised an indulgence and one year's remission of sin to those who fought the pagans. Those who died in this crusade would receive full indulgence:

The Battle of Stiklestad (Norwegian: Slaget på Stiklestad; Old Norse: Stiklarstaðir) in 1030 is one of the most famous battles in the history of Norway. In this battle, King Olaf II of Norway (Óláfr Haraldsson) was killed. During the pontificate of Pope Alexander III, the Roman Catholic Church declared Olaf a saint in 1164.

His younger half-brother, Harald Hardrada (Haraldr Haraldsson harðráði), was also present at the battle. Harald was only fifteen when the battle of Stiklestad took place. He became King of Norway in 1047, until his death in a failed invasion of England at the Battle of Stamford Bridge in 1066.