The Middle Ages was the period of European history from the coronation of Charlemagne in 800 to the invasion of Italy by the French in 1494.

Charlemagne or “Charles the Great” was King of all Franks. Charlemagne protected Pope St. Leo III and rescued him from his enemies.

Charlemagne was crowned on Christmas Day, 800, by Leo III. It was the beginning of the Holy Roman Empire. Though a soldier, Charlemagne’s interested was not only in war. He encouraged his people to become successful farmers; he was also a patron of learning and of arts.

Lay investiture
After the death of Charlemagne, the empire was governed by weak men and was divided. The raids by invaders such as the Vikings and the Saracens with no central authority to protect the people gave rise to the feudal system.

In the feudal system, common villagers would pay the landowner in labor or services in return for the landowner’s military protection against foreign or domestic enemies.

Some princes and kings, using their feudal authority, interfered with the appointment of bishops and abbots. “Lay investiture” is the appointment of bishops and abbots by secular rulers, often in exchange for temporal protection. This practice opened to the door of unworthy and worldly men being appointed to Church positions.

From the death of Pope Stephen IV in 817 to the accession of Pope Gregory VII in 1073, there was a dark period for the papacy. Aside from Pope St. Nicholas I (858-867), the popes of this period were either too weak or too corrupt to resist the emperor and the nobles. As a result of rival factions seeking control of the papacy, weak and unworthy men were often placed on the throne of St. Peter, and many of the popes were assassinated only after serving for a handful of days or months.

Gregorian Reform
Hildebrand (the future Gregory VII) was a monk. He carried out important tasks for different popes. In 1073, at the age of 53, he became Pope Gregory VII, and was the key figure in the “Gregorian Reform”—a seventy-five year struggle to recover the church her essential freedom in papal elections and appointments of Church offices.

Upon taking office, Gregory VII declared war on the three great evils of lay investiture, simony and concubinage. Emperor Henry IV opposed to the reform of Gregory VII against lay investiture.
Gregory excommunicated Henry and declared that his subjects no longer owed him obedience. It was the first time that an emperor was deposed by the pope. Henry came to Canossa to beg the pope for pardon. The pope granted him absolution.

However, Henry did not persevere and kept defying the laws of the Church. Gregory excommunicated him again in 1080. In 1084 Henry took Rome, and the aged pontiff was obliged to flee. On May 25, 1085, Pope Gregory VII died in exile. As he was dying, he said, “I have loved justice and hated iniquity, therefore I die in exile.”

About forty years later, the Concordat of Worms was called in 1122 under Pope Calixtus II and King Henry V to settle the matter of lay investiture. This first concordat in history established for all time Gregory VII’s principle that ecclesiastical jurisdiction does not derive from secular power.

Another hero during the struggle against lay investiture is St. Thomas Becket. At first he was a worldly and ambitious man, but with his episcopal ordination at forty-four, he was transformed.

Thomas Becket opposed Henry II’s attempt to gain control of the Church. In 1170 he was killed by the knights of the king at the foot of the altar. As he was dying, Thomas murmured, “I accept death for the name of Jesus and in defense of the Church.”

歐洲歷史從公元800年查理曼加冕起，至公元1494年法國入侵意大利，稱為「中世紀」時代。

查理曼亦即史稱查理大帝，他曾拯救了教宗聖良三世。公元800年聖誕日，教宗聖良三世把他加冕，成為神聖羅馬帝國的君王。

查理大帝雖是出身軍人，卻不熱衷打仗，反而關心農民，希望他們都能有豐盛的收成。他也大力支持了學術和藝術的發展。

俗權干預聖職

查理大帝駕崩後，繼承者均軟弱無能，日益分化，加上維京人和薩拉森人犯境，群雄無首，護民乏力；一般的農民，在此外憂內患情況下，為求得保生計，紛紛甘願依附不同的列強，成了他們的佃農。

有些皇族權貴，亦以軍力保護的權勢，干預教會晉立主教和院牧等職的神權，引致後來很多不稱職的神職人員，擅守教會的要職。

自教宗斯德望四世在公元817年死後，到公元1073年教宗國瑞七世開始，這段期間確實是教宗權力的黑暗期。除教宗聖尼閣一世(858-867) 外，當時在位的教宗，因軟弱或腐敗，無力與眾權貴抗衡；甚至因為不同的權貴角力，很多在位只有數月或數天的教宗被弒殺。

國瑞大革新

希德朋原是一位隱修士。他曾為多位教宗處理重要職務。在公元1073年五十三歲時，被推選為教宗，即教宗國瑞七世。他痛定思痛，進行鐵腕勵精圖治的革新，開始教廷七十五年撥亂反正的鬥爭，世稱國瑞大革新。教廷銳意取諦俗權干預聖權及聖職，當然遭到利益既得者的強烈反撲，但教宗國瑞七世無所懼怕：他把法國王帝亨利四世開除教藉，宣告民眾不用聽命於他。亨利四世大驚，親到嘉諾撒請罪，得教宗寬免。原來這是亨利四世緩兵之計，在穩固權力和兵力後，故態復萌。公元1080年，教宗國瑞七世再一次把亨利四世開除教藉。不過，亨利四世這次揮軍佔據羅馬，逼使年老的教宗逃亡公元1085年五月二十五日，教宗在放逐中離世，遺言：「因為我愛護正義，痛恨惡行，遂被流徙至死。」

約四十年後，公元1122年，教宗嘉禮二世與法國王帝亨利五世，簽署沃爾姆斯宗教協定，確立神權與俗權的分野，滿全了教宗聖國瑞七世的遺願，捍衛了教廷晉升牧職的神權。

另一名捍衛先烈是聖多默.貝克特大主教。他原是有俗世的野心，四十四歲時，被授予坎特伯里大主教牧職，全心轉化，努力對抗英皇亨利二世操控教會之心。公元1170年，亨利二世的武士們，把聖多默.貝克特刺殺，他死在祭台柱下。彌留時，他吐出心聲：「我因耶穌之名和捍衛教會而甘心接納死亡。」