Adrian IV is the only Englishman who has occupied the papal chair. It is generally believed that Nicholas Breakspear was born at Breakspear Farm in the parish of Abbots Langley in Hertfordshire and received his early education at the Abbey School, St Albans (St Albans School).
His reforming zeal as abbot led to the lodging of complaints against him at Rome; but these merely attracted to him the favourable attention of Pope Eugene III (1145–1153), who created him cardinal bishop of Albano in December 1149.
From 1152 to 1154 Nicholas was in Scandinavia as papal legate, organizing the affairs of the new Norwegian archbishopric of Nidaros (now Trondheim), creating the diocese at Hamar, and making arrangements which resulted in the recognition of Gamla Uppsala (later moved to Uppsala) as seat of the Swedish metropolitan in 1164. As a compensation for territory thus withdrawn, the Danish archbishop of Lund was made legate and perpetual vicar and given the title of primate of Denmark and Sweden.
In 1155, Byzantine Emperor Manuel Comnenus invaded Italy from the south, landing his forces in the region of Apulia. Making contact with local rebels who were hostile to the Sicilian crown, Byzantine forces quickly overran the coastlands and began striking inland. Pope Adrian IV watched these developments with some satisfaction. The Papacy was never on good terms with the Normans of Sicily, except when under duress by the threat of direct military action. Having the "civilised" Eastern Roman Empire on its southern border was infinitely preferable to Adrian than having to constantly deal with the troublesome Normans. Therefore, negotiations were hurriedly carried out, and an alliance was formed between Adrian and Manuel. Adrian undertook to raise a body of mercenary troops from Campania. Meanwhile, Manuel dreamed of restoration of the Roman Empire; this was, however, at the cost of a potential union between the Orthodox and the Catholic Church. Negotiations for union of the eastern and western churches, which had been in a state of schism since 1054, soon got underway. The combined Papal-Byzantine forces joined with the rebels against the Normans in Southern Italy, achieving a string of rapid successes as a number of cities yielded either to the threat of force or to the lure of gold. The future looked bleak for the Sicilians. It was at this point, just as the war seemed decided in the allies' favour, that things started to go wrong. The Byzantine commander Michael Palaeologus alienated some of his allies by his arrogance, and this stalled the campaign as rebel Count Robert of Loritello refused to speak to him. Although the two were reconciled, the campaign lost some of its momentum. Yet worse was to come: Michael was soon recalled to Constantinople. Although his arrogance had slowed the campaign, he was a brilliant general in the field, and his loss was a major blow to the allied campaign. The turning point was the Battle for Brindisi, where the Sicilians launched a major counter attack by both land and sea. At the approach of the enemy, the mercenaries that were serving in the allied armies demanded impossible rises in their pay. When this was refused, they deserted. Even the local barons started to melt away, and soon Adrian's Byzantine allies were left hopelessly outnumbered. The naval battle was decided in the Sicilians' favour, and the Byzantine commander was captured. The defeat at Brindisi put an end to the restored Byzantine reign in Italy, and by 1158 the Byzantine army had left Italy.
Hopes for a lasting alliance with the Byzantine Empire had also come up against insuperable problems. Pope Adrian IV's conditions for a union between the eastern and western church included recognition of his religious authority over all Christians everywhere, and the Emperor's recognition of his secular authority. Neither East nor West could accept such conditions. Adrian's secular powers were too valuable to be surrendered; Manuel's subjects could never have accepted the authority of the distant Pope in Rome. In spite of his friendliness towards the Roman church, Adrian never felt able to honour Manuel with the title of "Augustus". Ultimately, a deal proved elusive, and the two churches have remained divided ever since.
Henry II had no use for the bull until about 1170. At that time various English, Norman, and Welsh aristocrats had begun invading Ireland (c. 1166) because the deposed King of Leinster, Dermot MacMurrough, had asked them to help him regain his throne from his enemy High King of Ireland and King of Connacht Rory O'Connor. Henry was afraid these invaders would turn Ireland into a rival Norman state so he invaded Ireland himself in 1171, using the papal bull to claim sovereignty over the island, and forced the Anglo-Norman warlords and most of the Gaelic Irish kings to accept him as their overlord. Finally the Irish High King accepted Henry's overlordship in 1174 at the Treaty of Windsor.
In 1317 some Gaelic kings allied to Edward Bruce signed a document that asked the Pope to withdraw the effect of Laudabiliter. But the main effect from 1172 was financial, as much as political; the tithes, a form of Papal taxation, were applied to Ireland for the first time. To pay its way, Ireland started to use the feudal system. In this regard, Laudabiliter was similar to Adrian's work in Norway, bringing Christians at the edge of Europe into conformity with Rome, in terms of doctrine and taxation. The Irish church had been self-governing for centuries and had never paid its dues to Rome. But in Ireland since 1500 it has come to represent the start of Norman and English rule. Ireland was a feudal territory of the English monarch under the nominal overlordship of the papacy until 1541, when it became a kingdom belonging solely to the King of England.