Gregorian Reform in the context of "England in the Middle Ages"

England in the Middle Ages concerns the history of England during the medieval period, from the end of the 5th century through to the start of the early modern period in 1485. When England emerged from the collapse of the Roman Empire, the economy was in tatters and many of the towns abandoned. After several centuries of Germanic immigration, new identities and cultures began to emerge, developing into kingdoms that competed for power. A rich artistic culture flourished under the Anglo-Saxons, producing epic poems such as Beowulf and sophisticated metalwork. The Anglo-Saxons converted to Christianity in the 7th century, and a network of monasteries and convents were built across England. In the 8th and 9th centuries, England faced fierce Viking attacks, and the fighting lasted for many decades. Eventually, Wessex was established as the most powerful kingdom and promoted the growth of an English identity. Despite repeated crises of succession and a Danish seizure of power at the start of the 11th century, it can also be argued that by the 1060s England was a powerful, centralised state with a strong military and successful economy.

The Norman invasion of England in 1066 led to the defeat and replacement of the Anglo-Saxon elite with Norman and French nobles and their supporters. William the Conqueror and his successors took over the existing state system, repressing local revolts and controlling the population through a network of castles. The new rulers introduced a feudal approach to governing England, eradicating the practice of slavery, but creating a much wider body of unfree labourers called serfs. The position of women in society changed as laws regarding land and lordship shifted. England's population more than doubled during the 12th and 13th centuries, fueling an expansion of the towns, cities, and trade, helped by warmer temperatures across Northern Europe. A new wave of monasteries and friaries was established while ecclesiastical reforms led to tensions between successive kings and archbishops. Despite developments in England's governance and legal system, infighting between the Anglo-Norman elite resulted in multiple civil wars and the loss of Normandy.

Pope Gregory VII (Latin: Gregorius VII; c. 1015 – 25 May 1085), born Hildebrand of Sovana (Italian: Ildebrando di Soana), was head of the Catholic Church and ruler of the Papal States from 22 April 1073 to his death in 1085. He is venerated as a saint in the Catholic Church.

One of the great reforming popes, he initiated the Gregorian Reform, and is perhaps best known for the part he played in the Investiture Controversy, his dispute with Emperor Henry IV to establish the primacy of papal authority and the new canon law governing the election of the pope by the College of Cardinals. He was also at the forefront of developments in the relationship between the emperor and the papacy during the years before he became pope. He was the first pope to introduce a policy of obligatory celibacy for the clergy, which had until then commonly married, and also attacked the practice of simony.

Henry IV (German: Heinrich IV; 11 November 1050 – 7 August 1106) was Holy Roman Emperor from 1084 to 1105, King of Germany from 1054 to 1105, King of Italy and Burgundy from 1056 to 1105, and Duke of Bavaria from 1052 to 1054. He was the son of Henry III, Holy Roman Emperor—the second monarch of the Salian dynasty—and Agnes of Poitou. After his father's death on 5 October 1056, Henry was placed under his mother's guardianship. She made grants to German aristocrats to secure their support. Unlike her late husband, she could not control the election of the popes, thus the idea of the "liberty of the Church" strengthened during her rule. Taking advantage of her weakness, Archbishop Anno II of Cologne kidnapped Henry in April 1062. He administered Germany until Henry came of age in 1065.

Henry endeavoured to recover the royal estates that had been lost during his minority. He employed low-ranking officials to carry out his new policies, causing discontent in Saxony and Thuringia. Henry crushed a riot in Saxony in 1069 and overcame the rebellion of the Saxon aristocrat Otto of Nordheim in 1071. The appointment of commoners to high office offended German aristocrats, and many of them withdrew from Henry's court. He insisted on his royal prerogative to appoint bishops and abbots, although the reformist clerics condemned this practice as simony (a forbidden sale of church offices). Pope Alexander II blamed Henry's advisors for his acts and excommunicated them in early 1073. Henry's conflicts with the Holy See and the German dukes weakened his position and the Saxons rose up in open rebellion in the summer of 1074. Taking advantage of a quarrel between the Saxon aristocrats and peasantry, he forced the rebels into submission in October 1075.

Norman Irish or Hiberno-Normans (Irish: Normánach; Old Irish: Gall 'foreigners') is a modern term for the descendants of Norman settlers who arrived during the Anglo-Norman invasion of Ireland in the 12th century. Most came from England and Wales. They are distinguished from the native Gaelic Irish, although some Normans eventually became Gaelicised. The Hiberno-Normans were a feudal aristocracy and merchant oligarchy which controlled the Lordship of Ireland. The Hiberno-Normans were associated with the Gregorian Reform of the Catholic Church in Ireland and contributed to the emergence of a Hiberno-English dialect.

Some of the most prominent Hiberno-Norman families were the Burkes (de Burghs), Butlers, and FitzGeralds. One of the most common Irish surnames, Walsh, derives from Welsh Normans who arrived in Ireland as part of this group. Some Norman families were said to have become "more Irish than the Irish themselves" by merging culturally and intermarrying with the Gaels.

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.

The Davidian Revolution is a name given by many scholars to the changes which took place in the Kingdom of Scotland during the reign of David I (1124–1153). These included his foundation of burghs, implementation of the ideals of Gregorian Reform, foundation of monasteries, Normanisation of the Scottish government, and the introduction of feudalism through immigrant Norman and Anglo-Norman knights, as well as Flemish settlers.

The Catholic Church in Ireland, or Irish Catholic Church, is part of the worldwide Catholic Church in communion with the Holy See. With approximately 4.3 million members, it is the largest Christian church in Ireland. In the Republic of Ireland's 2022 census, 69% of the population identified as Roman Catholic, and in Northern Ireland's 2021 census, 42.3% identified as Roman Catholic.

The Archbishop of Armagh, as the Primate of All Ireland, has ceremonial precedence in the church. The church is administered on an all-Ireland basis. The Irish Catholic Bishops' Conference is a consultative body for ordinaries in Ireland.Christianity has existed in Ireland since the 5th century and arrived from Roman Britain (most famously associated with Saint Patrick), forming what is today known as Gaelic Christianity. It gradually gained ground and replaced the old pagan traditions. The Catholic Church in Ireland cites its origin to this period and considers Palladius as the first bishop sent to the Gaels by Pope Celestine I. However, during the 12th century a stricter uniformity in the Western Church was enforced, with the diocesan structure introduced with the Synod of Ráth Breasail in 1111 and culminating with the Gregorian Reform which coincided with the Anglo-Norman invasion of Ireland.

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).