Pope Gregory VII in the context of "Kingdom of Germany"

The history of Italy in the Middle Ages can be roughly defined as the time between the collapse of the Western Roman Empire and the Italian Renaissance. Late antiquity in Italy lingered on into the 7th century under the Ostrogothic Kingdom and the Byzantine Empire under the Justinian dynasty, the Byzantine Papacy until the mid 8th century. The "Middle Ages" proper begin as the Byzantine Empire was weakening under the pressure of the Muslim conquests, and most of the Exarchate of Ravenna finally fell under Lombard rule in 751. From this period, former states that were part of the Exarchate and were not conquered by the Lombard Kingdom, such as the Duchy of Naples, became de facto independent states, having less and less interference from the Eastern Roman Empire.

Lombard rule ended with the invasion of Charlemagne in 773, who established the Kingdom of Italy and the Papal States in large parts of Northern and Central Italy. This set the precedent for the main political conflict in Italy over the following centuries, between the Pope and the Holy Roman Emperor, culminating with conflict between Pope Gregory VII and Henry IV and the latter's "Walk to Canossa" in 1077.

The magisterium of the Catholic Church is the church's authority or office to give authentic interpretation of the word of God, "whether in its written form or in the form of Tradition". According to the 1992 Catechism of the Catholic Church, the task of interpretation is vested uniquely in the Pope and the bishops, though the concept has a complex history of development. Scripture and Tradition "make up a single sacred deposit of the Word of God, which is entrusted to the Church", and the magisterium is not independent of this, since "all that it proposes for belief as being divinely revealed is derived from this single deposit of faith."

Matilda of Tuscany (Italian: Matilde di Toscana; Latin: Matilda or Mathilda; c. 1046 – 24 July 1115), or Matilda of Canossa (Italian: Matilde di Canossa [maˈtilde di kaˈnɔssa]), also referred to as la Gran Contessa ("the Great Countess"), was a member of the House of Canossa (also known as the Attonids) in the second half of the eleventh century. Matilda was one of the most important governing figures of the Italian Middle Ages. She reigned in a time of constant battles, political intrigues, and excommunications by the Church.

She ruled as a feudal margravine and, as a relative of the imperial Salian dynasty, she brokered a settlement in the so-called Investiture Controversy. In this extensive conflict with the emerging reform Papacy over the relationship between spiritual (sacerdotium) and secular (regnum) power, Pope Gregory VII dismissed and excommunicated the Holy Roman Emperor Henry IV (then King of the Romans) in 1076. At the same time, Matilda came into possession of a substantial territory that included present-day Lombardy, Emilia, Romagna, and Tuscany. She made the Canossa Castle, in the Apennines south west of Reggio Emilia, the centre of her domains.

The Investiture Controversy or Investiture Contest (Latin: Controversia de Investitura, German: Investiturstreit, pronounced [ɪnvɛstiˈtuːɐ̯ˌʃtʁaɪt] ) was a conflict between the Church and the state in medieval Europe over the ability to choose and install bishops (investiture), abbots of monasteries, and the Pope himself. A series of popes in the 11th and 12th centuries undercut the power of the Holy Roman Emperor and other European monarchies, and the controversy led to nearly 50 years of conflict.

It began as a power struggle between Pope Gregory VII and Henry IV (then King, later Holy Roman Emperor) in 1076. The conflict ended in 1122, when Pope Callixtus II and Emperor Henry V agreed on the Concordat of Worms. The agreement required bishops to swear an oath of fealty to the secular monarch, who held authority "by the lance" but left selection to the church. It affirmed the right of the church to invest bishops with sacred authority, symbolized by a ring and staff. In Germany (but not Italy and Burgundy), the Emperor also retained the right to preside over elections of abbots and bishops by church authorities, and to arbitrate disputes. Holy Roman Emperors renounced the right to choose the Pope.

Pope Gregory IX (Latin: Gregorius IX; born Ugolino di Conti; 1145 – 22 August 1241) was head of the Catholic Church and the ruler of the Papal States from 19 March 1227 until his death in 1241. He is known for issuing the Decretales and instituting the Papal Inquisition, in response to the failures of the episcopal inquisitions established during the time of Pope Lucius III, by means of the papal bull Ad abolendam, issued in 1184.

He worked initially as a cardinal, and after becoming the successor of Honorius III, he fully inherited the traditions of Gregory VII and of his own cousin Innocent III, and zealously continued their policy of papal supremacy.

The Road to Canossa or Humiliation of Canossa (Italian: L'umiliazione di Canossa), or, sometimes, the Walk to Canossa (German: Gang nach Canossa/Kanossa) was the journey of the Holy Roman Emperor Henry IV to Canossa Castle in 1077, and his subsequent ritual submission there to Pope Gregory VII. It took place during the Investiture controversy and involved the Emperor seeking absolution and the revocation of his excommunication by the Pope who had been staying at the castle as the guest of Margravine Matilda of Tuscany.

According to contemporary sources, he was forced to supplicate on his knees, waiting for three days and nights before the castle gate while a blizzard raged, "one of the most dramatic moments of the Middle Ages". The episode has spurred much debate among medieval chroniclers as well as modern historians, who dispute whether the walk was a humiliating defeat for the emperor or a "brilliant masterstroke".

Mihailo Vojislavljević (Serbian Cyrillic: Михаило Војислављевић) was a medieval Serbian king and the ruler of Dioclea (Duklja), from 1046 to 1081, initially as a Byzantine vassal holding the title of protospatharios, then after 1077 as nominally serving Pope Gregory VII, styled as "King of the Slavs". He had alienated himself from the Byzantines when he supported the Bulgarian Uprising of Georgi Voyteh, after which he then sought to gain support in the West. In 1077 he received royal insignia by Gregory VII in the aftermath of the Church schism of 1054.