Pope Adrian IV in the context of "Henry (bishop of Finland)"

The Kingdom of Ireland (Early Modern Irish: Ríoghacht Éireann; Modern Irish: Ríocht na hÉireann, pronounced [ənˠ ˌɾˠiːxt̪ˠ ˈeːɾʲən̪ˠ]) was a dependency of England from 1542 to 1707, and subsequently Great Britain from 1707 to 1800. It was ruled by the monarchs of England and then of Great Britain in personal union, and was administered from Dublin Castle by a viceroy appointed by the English king: the Lord Lieutenant of Ireland. By the late 17th century, the state was dominated by the Protestant Anglo-Irish minority, known as the Protestant Ascendancy. The Protestant Church of Ireland was the state church. The Parliament of Ireland was almost exclusively Anglo-Irish. From 1661, the administration controlled an Irish army. Although formally a kingdom in personal union on equal footing with England and later Great Britain, for most of its history it was de facto a dependency with a viceroy sent as an envoy from London. This status was enshrined in the Declaratory Act 1719, also known as the Irish Parliament Act 1719.

The territory of the kingdom comprised that of the former Lordship of Ireland, founded in 1177 by King Henry II of England and the English Pope Adrian IV, after the Anglo-Norman invasion of Ireland. By the 16th century, the Pale, the area of effective English rule, had shrunk greatly; most of Ireland was held by Gaelic nobles as minor principalities notionally subject to London but independent in practice. By the terms of the Crown of Ireland Act 1542, Henry VIII of England became "King of Ireland", theoretically elevating Ireland to coequal status with England as a kingdom in personal union. There followed an expansion of English control during the Tudor conquest. This sparked the Desmond Rebellions and the Nine Years' War. The conquest of the island was completed early in the 17th century. It involved the confiscation of land from the native Irish Catholics and its colonisation by Protestant settlers from Britain. Most Catholic countries at the time did not recognise Protestant monarchs as legitimate kings of Ireland (or indeed of England), instead supporting the Jacobite government-in-exile from 1688 onwards.

Frederick Barbarossa (December 1122 – 10 June 1190), also known as Frederick I (German: Friedrich I; Italian: Federico I), was the Holy Roman Emperor from 1155 until his death in 1190. He was elected King of Germany in Frankfurt on 4 March 1152 and crowned in Aachen on 9 March 1152. He was crowned King of Italy on 24 April 1155 in Pavia and emperor by Pope Adrian IV on 18 June 1155 in Rome. Two years later, the term sacrum ("holy") first appeared in a document in connection with his empire. He was later formally crowned King of Burgundy, at Arles on 30 June 1178. His nickname of Barbarossa (meaning "Red Beard" in Italian) "was first used by the Florentines only in 1298 to differentiate the emperor from his grandson, Frederick II ... and was never employed in medieval Germany" (the colour red was "also associated in the Middle Ages with malice and a hot temper"; in reality, Frederick's hair was "blond", although his beard was described by a contemporary as "reddish"). In German, he was known as Kaiser Rotbart, which in English means "Emperor Redbeard". The prevalence of the Italian nickname, even in later German usage, reflects the centrality of the Italian campaigns under his reign, and "remains to this day one of the [most] powerful historical monikers."

Frederick was by inheritance Duke of Swabia (1147–1152, as Frederick III) before his imperial election in 1152. He was the son of Duke Frederick II of the Hohenstaufen dynasty and Judith, daughter of Henry IX, Duke of Bavaria, from the rival House of Welf. Frederick, therefore, descended from the two leading families in Germany, making him an acceptable choice for the Empire's prince-electors. Frederick joined the Third Crusade and opted to travel overland to the Holy Land. In 1190, Frederick drowned attempting to cross the Saleph River, leading to most of his army abandoning the Crusade before reaching Acre.

Manuel I Komnenos (Greek: Μανουήλ Κομνηνός, romanized: Manouḗl Komnēnós; 28 November 1118 – 24 September 1180), Latinized as Comnenus, also called Porphyrogenitus (Greek: Πορφυρογέννητος, romanized: Porphyrogénnētos; "born in the purple"), was a Byzantine emperor of the 12th century who reigned over a crucial turning point in the history of Byzantium and the Mediterranean. His reign saw the last flowering of the Komnenian restoration, during which the Byzantine Empire experienced a resurgence of military and economic power and enjoyed a cultural revival.

Eager to restore his empire to its past glories as the great power of the Mediterranean world, Manuel pursued an energetic and ambitious foreign policy. In the process he made alliances with Pope Adrian IV and the resurgent West. He invaded the Norman Kingdom of Sicily, although unsuccessfully, being the last Eastern Roman emperor to attempt reconquests in the western Mediterranean. The passage of the potentially dangerous Second Crusade through his empire was adroitly managed. Manuel established a Byzantine protectorate over the Crusader states of Outremer. Facing Muslim advances in the Holy Land, he made common cause with the Kingdom of Jerusalem and participated in a combined invasion of Fatimid Egypt. Manuel reshaped the political maps of the Balkans and the eastern Mediterranean, placing the kingdoms of Hungary and Outremer under Byzantine hegemony and campaigning aggressively against his neighbours both in the west and in the east.

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 papal election held from 4 to 7 September 1159 following the death of Pope Adrian IV resulted in the election of two rival popes. A majority of the cardinals elected Cardinal Rolando of Siena as Pope Alexander III, but a minority refused to recognize him and elected their own candidate, Ottaviano de Monticelli, who took the name Victor IV, creating a schism that lasted until 1178.

The schism was a result of the growing tensions inside the Sacred College of Cardinals concerning the foreign policy of the Holy See. The Papal States in the 12th century were a buffer between the Holy Roman Empire and the Norman Kingdom of Sicily. After the Concordat of Worms in 1122, the Papacy allied with the Empire rather than with the Normans, but during the pontificate of Adrian IV (1154–59) this alliance broke up because Emperor Frederick I Barbarossa did not fulfil the terms of the treaty of Constance (1153) that obliged him to help the Papacy to restore its authority in Rome and in other territories controlled by the king of Sicily. In these circumstances Adrian IV decided to break the alliance with the Emperor and to make peace with William I of Sicily by signing the Treaty of Benevento (1156). In the following years there were growing tensions between the papacy and Emperor Frederick I Barbarossa (e.g. a dispute at the diet of Besançon in 1157). Frederick tried – with significant success – to strengthen his influence on the Church in Germany. The change of direction of the papal foreign policy resulted in the division of the Sacred College into supporters and opponents of the new policy, who were unable to achieve a compromise after the death of Adrian IV.

The Third Council of the Lateran met in Rome in March 1179. Pope Alexander III presided and 302 bishops attended. The Catholic Church regards it as the eleventh ecumenical council.

By agreement reached at the Peace of Venice in 1177 the bitter conflict between Alexander III and Emperor Frederick I was brought to an end. When Pope Adrian IV died in 1159, the divided cardinals elected two popes: Roland of Siena, who took the name of Alexander III, and Octavian of Rome who, though nominated by fewer cardinals, was supported by Frederick and assumed the name of Pope Victor IV. Frederick, wishing to remove all that stood in the way of his authority in Italy, declared war upon the Italian states and especially the Church which was enjoying great authority. A serious schism arose out of this conflict, and after Victor IV's death in 1164, two further antipopes were nominated in opposition to Alexander III: Paschal III (1164–1168) and Callistus III (1168–1178). Eventually, at the Peace of Venice, when Alexander gained victory, he promised Frederick that he would summon an ecumenical council.