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It is best to describe this period in Church History in Three Parts:

Part I – The Western Church During the Dark Ages

Part II – The Eastern Church During the Dark Ages

Part III – The Christianization of New Nations

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Charlemagne and the Holy Roman Empire

On Christmas day, A.D. 800, Pope Leo III crowned Charlemagne as the new emperor in the West. To distinguish the new Empire of Charlemagne from the defunct Western Roman Empire, the new Empire has been called the Holy Roman Empire. There were, therefore, two emperors again in the Roman Empire, one in the east and one in the west. (See Map for the dividing line between the East and the West.) However, the Byzantine Emperor was not too happy about having a second ruler in the empire. At first, he did not want to recognize the new Western Emperor, but he did so eventually in A.D. 812 when the territories of Venice and Dalmatia were returned

The Coronation of Charlemagne

A paining by Raphael (1483-1520)

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There was peace in the Holy Roman Empire while Charlemagne lived. The Muslims were kept in check; the pope ruled over the Papal States, while the two emperors governed their respective territories in the Christian Empire. The world understood that the pope was supreme in the spiritual order and the emperors were supreme in the temporal order. Charlemagne protected Rome and the Papal States from their enemies while respecting the temporal power of the pope over them.

Charlemagne’s Successors and the Rise of Feudalism

Things changed drastically after Charlemagne died in A.D. 814. At first, the leadership of the Western Empire was passed on to Charlemagne’s son, King Louis. Then the Empire was divided among Louis’ sons (Lothair, Louis the German, and Charles the Bald). Over time, the Western Roman Empire was broken up into several smaller kingdoms in various countries, with each ruler claiming a distant kinship with Charlemagne. Of course, there was always a Holy Roman Emperor, but this was reduced to a position of honor rather than a position of dominance over the kings of smaller kingdoms.

Charlemagne’s successors were not the strong military rulers that Charlemagne was. So, the persecution of Christians by Muslims resumed. Also, the divisions in the Empire weakened it and made Europe vulnerable to attack by Viking and Norman invaders from the north, a condition that continued until the end of the 11th century. (Note: The Normans were Vikings who mixed with the local natives: the Franks and the Gauls.)

In the absence of a strong central power that could resist foreign invaders, people often had to defend themselves. This gave rise to the so-called feudal system, or feudalism. Under this system, powerful and wealthy individuals became local leaders in various communities. These leaders built castles that served as a military stronghold against foreign invaders. Farmers from the surrounding countryside supported their local leaders and sought refuge in these castles when attacked by invaders. In exchange for the local leader’s protection, the farmers were required to deed their land, known as a fief, to their local leader and to render military service during an invasion. The farmers were still allowed to work on the land but were required to give a portion of the crops they produced each year to their leader.

When the invaders were stronger than one local leader could resist, several local leaders banded themselves together under a greater or more powerful leader, called a duke or count. Just as the farmers were required to surrender their land and render services to their local leader in return for military protection, the local leaders were also required to deed their respective territories and swear loyalty and support to the duke to obtain the duke’s protection. The promise of loyalty and support is called fealty. The duke, who received the allegiance and support of the local leaders, was known as an overlord or feudal lord, and the vast territory of land he received from the local leaders was known as a manor. The local leaders who deeded their land to the duke became his vassals, while the farmers who worked on the land were called serfs.

The powerful overlords, in turn, served the king. These noblemen also swore fealty to the king and served as the king’s vassals. Feudalism was therefore a tiered system where those in the lower level surrendered lands and swore fealty to the nobles in the higher tier. Those who owned no land but who wanted the protection of the overlord had to provide military service in return. They were usually soldiers on horseback and were known as knights. They proved to be invaluable to the king, not only during the Viking and Norman invasions but also during the time of the Crusades.

The Church under the Feudal System

Although feudalism was criticized for being exploitative and unfair, especially to the serfs, it helped Europe repel and survive those devastating Viking raids. However, as far as its effect on the Church is concerned, feudalism has done more harm than good. This is because the bishops and other members of the clergy also became feudal lords. Thus, their attention was divided between their duties to God and the feudal services they had to do for their subjects. Worse, bishops became vassals of greater lords. As such, they often got involved in the disputes and rivalry that existed between various overlords and vassals of the king.

As vassals of the king, bishops also had to promise fealty to the king and other secular lords. This effectively made them servants of the king. This arrangement also paved the way for the frequent interference by civil authorities in the affairs of the Church, especially in the election of the pope, bishops, and the appointment of the clergy. Emperors sometimes interfered with church matters in their desire to regain control of the Papal States. They felt that if they were to be the protectors of the Papal States, then they should also have a voice in choosing who the next pope should be. Thus, they either used their overwhelming influence or sometimes put up their candidates for the papacy. This was known as the act of lay investiture, in which personnel for ecclesiastical positions were selected and bestowed not by the clergy but lay rulers. This practice resulted in incompetent or unqualified individuals being selected for important Church positions, including the papacy.

Good Popes and Bad Popes

The ninth century did not merely show a decline among the temporal leaders in the Western Empire. As a result of the feudalistic system shortly after the death of Charlemagne, there was also a moral decline among the spiritual leaders of the Church. Churchmen, including bishops, lived worldly lives. Some popes were greedy and immoral, and some were incompetent. It was a very bad time for the Catholic Church. If there was a period in Church history that might be described as the “Dark Ages,” it would be the period from the middle of the ninth century to the middle of the eleventh century.

However, there were also good popes during this period. For example, in A.D. 858, St. Nicholas I (A.D. 800–867) was elected pope. Unlike most popes during this period, Pope St. Nicholas I (aka Pope St. Nicholas the Great) was a God-fearing and righteous man and was ready to denounce all wrongdoers. There was one incident that illustrates his bravery. One of Charlemagne’s great-grandsons, Lothair II, wanted to divorce his wife. But after studying the details of his case, Pope Nicholas found out that his marriage had been valid. Therefore, he courageously refused to grant the divorce and defended the indissolubility of marriage against the king. Disappointed, Lothair sent his army to Rome to frighten the pope, but Pope St. Nicholas I heroically held his position and did not yield.

Good Pope St. Nicholas I

Portrait in the Basilica of St. Peter Outside the Walls

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As stated earlier, some Popes of the ninth, tenth, and eleventh centuries were bad or unholy. This is the reason why this period was aptly called the “Dark Ages” in the Church’s history. For, although the Church in past centuries also faced crises, persecution, and near extinction (during the Roman persecution, the age of heresies, and the barbarian invasions), there was never a time in prior Church history when the hierarchy and the papacy itself were, in a sense, engulfed in darkness, particularly moral and spiritual darkness.

One important reason why the Church began to be led by corrupt and immoral popes was the interference by civil rulers and by the emperor in the election of a new pope. It used to be the case that only the clergy could elect the pope. But in the ninth century, as a result of the feudal system that became prevalent in Europe at that time, the practice of permitting the nobility to take part in the election started. Sometimes, even if the new pope was chosen by the clergy, the election was not considered final until the bureaucratic emperor’s representative was satisfied with the result. There had also been times when competing political parties caused the election of two different popes! With the pope of their choice in office, civil rulers were able to control the appointment of other members of the hierarchy. Bishops and priests were appointed who were incompetent, who could be bribed, or who would enact policies dictated by powerful officials in the government.

Some of the unholy Popes during this period were the following: Pope Stephen VII, who exhumed his predecessor’s body and called a “Cadaver Synod" to give the corpse a mock trial; Pope John XII, who became pope at the age of 18 and was caught in bed with another man’s wife; Pope Benedict IX, who not only was rumored to have engaged in sodomy and adultery but who also sold and resigned his papacy to his grandfather—Pope Gregory VI—for a large sum of money.


The corruption in the Church was not limited to the papacy. Many of the writings against homosexuality, sodomy, and sexual immorality written by St. Peter Damian, a Doctor of the Church, referred precisely to the kind of sexual abuses that he witnessed among the clergy during the mid-eleventh century. Sadly, this spiritual disease, first noted in Sodom and Gomorrah, continues to the present!

There had been other bad popes after the so-called “Dark Ages,” but these were isolated cases and were due more to the bad practice of nepotism and the personal misbehavior of the individual popes than to the interference in the papal election by the ruling elite. However, it was on account of these bad popes that many people mistakenly called the entire Middle Ages, which covered the period from 800 to 1500, the “Dark Ages.” It is widely believed that the misbehavior of some of these popes also triggered the Protestant Reformation in the sixteenth century.

Pope St. Gregory VII and the End of Lay-Investiture

The first person to make an all-out attack on the evil of lay investiture was Pope St. Gregory VII (1015–1085). Born Hildebrand, he studied in a monastery in Rome and later became secretary to the pope, where he learned firsthand about the problems that were hurting the Church. Because of his intelligence, he became an adviser to other popes before him. When he became the pope, he denounced lay investiture, saying that no layman had the authority to give a bishop his ring and crozier (the hooked staff), which were the symbols of his spiritual authority. He deposed all bishops who received their authority at the hands of secular rulers and threatened to excommunicate any layperson (including princes and kings) who would persist in the practice of conferring spiritual authority on anyone. One of those who defied him was King Henry IV of Germany. As a result, Pope Gregory excommunicated him. When King Henry fought back and tried to depose Gregory, he found himself without supporters and was even faced with a revolt among his subjects and those loyal to the pope. To help himself get out of trouble, Henry begged Pope Gregory for forgiveness. Although it was winter, Henry, barefooted and dressed in a penitent’s gown, stood for three days outside the pope’s palace, waiting for the pope’s response. Pope Gregory did forgive him, but King Henry was not sorry. He soon started appointing church officials again in Germany. He tried to depose Pope Gregory and sent his army to Rome. He captured Rome in 1084. Pope Gregory fled first to the Castle of St. Angelo, then to Monte Cassino, and afterward to Salerno, where he died in exile the following year.

King Henry IV Waiting for 3 Days Outside the Pope's Palace Begging for Forgiveness

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In 1059, Pope Nicholas II continued the work that Pope Gregory started. In a document, In nomine Domini, Pope Nicholas established new laws for the election of a pope and disqualified secular and lay nobles as electors. He designated the “cardinals” (those high members of the Church who work closely with the pope in Rome) as the sole electors for the pope. But the struggle for lay investiture continued in France and England, but mostly in Germany. The problem was finally resolved in the twelfth century when Emperor Henry V and Pope Calixtus II signed a treaty known as the Concordat of Worms (1122), a treaty that confirmed the independence of the Church from the State, and which was also sanctioned by the First Council of Lateran in Rome (1123). In this treaty, the emperor was allowed to be present, but not to vote, during the election of popes and bishops and to invest the bishop with the scepter, which is a symbol of temporal authority. In turn, the emperor agreed to permit the free election of church officials by giving up the investiture of the ring and the crozier, which are symbols of religious authority, to the Church.

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The Eastern Church during the Dark Ages

Like the Roman Church, which suffered from the interference of the Roman emperors, the Eastern Church in Constantinople (now Istanbul, Turkey) also suffered from the interference of the Byzantine emperors during the ninth and tenth centuries. Even in the fourth century, the Byzantine emperors had already shown a tendency to meddle with the Church of Constantinople. They found it hard to accept that there could be another authority higher than theirs. So, they expected the patriarch and bishops of Constantinople to always comply with their wishes. The Byzantine emperors also expected the pope in Rome to be more submissive, since they now regarded Constantinople, rather than Rome, as the center of Christendom. The intransigence of the Roman Pontiff was often viewed as defiance of their authority. A case in point happened in the eighth century when Pope Gregory II opposed the heresy of iconoclasm, which the Byzantine emperor patronized and the Eastern bishops supported. Needless to say, this episode worsened the relationship not only between the Byzantine Empire and the papacy but also between the Church of Constantinople and the Church of Rome.

Another illustration of how the Byzantine emperor meddled with church affairs happened during the pontificate of Pope St. Nicholas I in the ninth century. At this time, the emperor’s regent was Bardas, the uncle and tutor of the young Emperor Michael III. Bardas replaced his sister, St. Theodora, the mother of Michael III, as regent when St. Theodora entered the convent. Now, when St. Ignatius, Patriarch of Constantinople, condemned Bardas for divorcing his wife and having an incestuous relationship with his daughter-in-law, Bardas banished him to the island of Terebinthus. Then he selected Photius, who was a learned man but not a priest, to take his place as patriarch. Some of the bishops supported Photius, but other bishops objected, saying that Photius’ election was inappropriate since he was hurriedly ordained priest and bishop on the same day. Perhaps the election of Photius was uncanonical, but it wasn’t unlawful because Ignatius (who was in exile) had already resigned his position when Photius was elected. When Pope St. Nicholas I heard about the deposition of St. Ignatius, he investigated the case but, not knowing that Ignatius had voluntarily resigned the patriarchate during his exile, pronounced him to be the legitimate Patriarch of Constantinople. Despite this misunderstanding, the facts became clear later, and the Fourth Council of Constantinople (A.D. 869–870) under Pope Adrian II eventually deposed Photius and reinstated St. Ignatius in the See of Constantinople.

Roots of the Greek Schism

The great split between the Eastern and Roman Churches, known as the Greek or Eastern Schism, did not happen until the eleventh century. However, this unfortunate split, which has lasted until the present day, has been slowly building up since the time of Photius.

In A.D. 866, while Photius was the Patriarch of Constantinople, Boris, the King of Bulgaria, expelled the Greek missionaries from his country and replaced them with missionaries from Rome. Photius became angry because he wanted Bulgaria to be under the spiritual leadership of Constantinople. As a reaction to this event, he issued a letter, known today as the Encyclical of Photius, against the Roman bishops in which he exposed what he thought were the bad customs and heretical doctrines of the Roman missionaries. The “bad customs” included, among others, not fasting strictly during Lent. The “heretical doctrines” referred to the addition by the Roman Church of the word Filioque to the Nicene Creed, which indicated that the Holy Spirit proceeded from the Father and the Son. Photius and some of the Eastern bishops thought that this was an unnecessary and heretical addition and that the Holy Spirit proceeds from the Father alone. After writing his encyclical, Photius called a synod of all the bishops of the Eastern Empire, in which he tried to excommunicate Pope Nicholas for this “heresy.”

In A.D. 867, Pope St. Nicholas died, and Emperor Michael III was assassinated. Pope Adrian II, who succeeded Pope St. Nicholas, called the Fourth Council of Constantinople, which condemned the errors of Photius and reinstated Ignatius as the Patriarch of Constantinople. The new Emperor Basil promised Photius that he would be patriarch again after Ignatius died. Then, in a synod held at Constantinople under Pope John VIII, a settlement was made between Ignatius, Photius, and the pope, which resulted in peace between Constantinople and Rome for about 150 years until the final breakup between the East and the West in 1054.

The Greek or Eastern Schism of 1054

Although there had been peace between the Eastern Church and Rome after Photius, ill feelings and jealousy persisted between them. The roots of this ill feeling may be traced back even to the fourth century, when, in the Council of Nicea, Rome condemned many heresies that had sprung up from the East.

In 1053, Michael Cerularius, the Patriarch of Constantinople, began criticizing the Latin Rite’s use of unleavened bread for Holy Communion, claiming that this was Jewish superstition. Then, he closed all the Latin churches in Constantinople, which caused Pope St. Leo IX to send his delegates to investigate the trouble. The head of the pope’s delegation was Cardinal Humbert, who quickly developed an antipathy for the patriarch. The result was an exchange of excommunication between them. In 1054, Cardinal Humbert excommunicated Cerularius and his followers. In return, Cerularius excommunicated Humbert and the other delegates. 

Hagia Sophia (or "Holy Wisdom")

Now a museum, but formerly the Eastern Orthodox Cathedral and Seat of Patriarch Michael Cerularius of Constantinople; Photo by Arild Vâgen, 2013

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The fight resulted more from a clash of personalities than from doctrinal issues. Yet, this unfortunate event caused a split between the Eastern and Western Churches that, except for a brief period, lasted for centuries until the present day. That brief period was in 1439, when the Greek bishops were received back into full union with Rome at the Council of Florence (1438–1445). But this lasted only a few years, and the schism resumed.


Remarkably, Roman Catholic and Orthodox Christians have so much in common. They both hold the same faith, worship the same God, partake of the same sacraments, have valid holy orders, and are one in their devotion to the Mother of God. Yet, they are not completely in communion with each other because Roman Catholics are unyielding in their affirmation regarding the supremacy of the Roman Pontiff. On the other hand, the Orthodox Christians are willing to say that the Pope is first among equals (that is, equal to the Patriarchs), but not that he is supreme. Today, an effort is still being made on both sides to achieve Christian unity. The cordial meeting and fraternal embrace between Patriarch Athenagoras I and Pope Paul VI in 1964 was a sign of this continuing effort toward Christian unity. On December 7, 1965, in a gesture of goodwill and desire for unity, both Pope Paul VI and the Eastern Patriarch mutually lifted and nullified the excommunications that both Christian bodies hurled against each other in 1054.

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Conversion of the Scandinavian Countries

Notwithstanding the deplorable state of the Church during the ninth, tenth, and eleventh centuries, the Christianization of the northern states in Europe continued. The conversion of the Scandinavian countries (Denmark, Norway, and Sweden) began in the ninth century. See Map.

The conversion of Denmark started in A.D. 826, when King Harald Klak Halfdansson (A.D. 785-852), King of Jutland and parts of Denmark, sought refuge in the court of King Louis I (aka King Louis the Pious) of France. King Louis, who was the son of Charlemagne, promised King Harald that he would help him recover his kingdom if he converted to Christianity. King Harald accepted this condition and was baptized along with four hundred of his attendants. When he returned to Denmark, he took along a pious monk, St. Ansgar (A.D. 801–865), to preach Christianity there. St. Ansgar worked tirelessly for forty years as a missionary among the Danes and the Swedes. It was a difficult job because it was during this time that the Vikings and Norman pirates were marauding the coastlands of Europe, destroying churches, and driving the monks and converts out of Scandinavia. But due to his work, Denmark was converted, and then Norway and Sweden. For this reason, St. Ansgar is fittingly called the Apostle of the North.

Conversion of the Slavic Nations

The Slavic nations include the following countries: In the east: European Russia, Ukraine, and Belarus; in the west: Poland, the Czech Republic (including Bohemia, Moravia, and Czech Silesia), Slovakia, and Serbia; in the south: Slovenia, Croatia, Bosnia, Macedonia, and Montenegro. See Map.

St. Cyril the Philosopher (A.D. 827–869) and St. Methodius of Thessalonica (A.D. 815–884) were missionaries who worked in Moravia, which is part of the Czech Republic. They were brothers, and, although born in Thessalonica (in Greece, near the Slav border), they knew the language and customs of the Slavs. St. Cyril invented the Slav alphabet (which the Russians still use today) and used it to write Bible readings and prayers in the Slavonic language. The Frankish king and the bishops objected to the use of Slavonic language in the Mass, but Saints Cyril and Methodius got permission from Pope Adrian II to use the vernacular in the liturgy. St. Cyril died when they were in Rome, but St. Methodius continued the work of evangelizing the Slavs. After St. Methodius’ death, the Slavonic liturgy was replaced by Latin, although some of his disciples introduced it among the Jugo-Slavs, where it is still in limited use. Thanks to Saints Cyril and Methodius and their disciples, the message of the gospel was slowly received in other Slavic-speaking nations. Saints Cyril and Methodius became known as the Apostles of the Slavs. In 1985, Pope John Paul II also named them, together with St. Benedict, co-patrons of Europe.

See Pope St. John Paul II, Slavorum Apostoli.

St. Cyril and St. Methodius

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The conversion of Poland started late in the tenth century when Mieszko, the ruler of Poland, married a Christian Bohemian princess named Doubravka (or Dobrawa) in A.D. 965. Although many believe that Miezsko’s conversion to Christianity was due to Doubravka’s influence, others believe that Miezsko’s conversion was done solely for political reasons. Whatever the true motivation was, it is also true that, through his conversion, Christianity got a foothold in Poland, although not without resistance. With the help of King Henry III, King Casimir I (1040–1058) succeeded in suppressing a strong pagan uprising. Ever since then, Poland has remained a Christian nation.

The conversion of Russia also started late in the tenth century. When the Vikings invaded that part of Russia that is now known as Ukraine, one of the chieftains, Oleg, captured the city of Kyiv and brought other territories around it to form what came to be called “Russia.” Oleg’s successor, named Igor, married St. Olga (A.D. 890–969), who was baptized in Constantinople in A.D. 957. At her request, missionaries came to her husband’s kingdom and brought Christianity to Kyiv. In A.D. 988, her grandson, Vladimir, married the sister of the Greek Emperor Basil II and was baptized on their wedding day. Through his influence, most of Russia also became Catholic. But, due to little or poor religious instruction, many of the Russians remained nominal Catholics only but pagan in practice. Also, the first archbishops of Kyiv were Greeks. Thus, when the Greeks broke off with the Roman Catholic Church in the great schism of 1054, the Russian Church also broke off with Rome.


Conversion of Hungary

Toward the end of the tenth century, the Magyars, who settled in Hungary around A.D. 900, had been making constant attacks on their neighbors and were regarded as a threat to Christianity. The Western Roman Emperor Otto I put an end to their hostility by defeating their army in a battle at the Lech River in A.D. 955. Since then, the Magyars have lived quietly as farmers in Hungary and welcomed missionaries who came to the country. One of these missionaries was Pilgrim of Passau, who converted numerous pagans in Hungary. One of the converts was the holy King Stephen (A.D. 997–1038), during whose reign Catholicism flourished in Hungary. Monasteries were built, and dioceses were established. Although paganism was revived for a short time after his death, it was crushed again by yet another holy king, St. Ladislaus (1077–1095).

Revitalization of Monasticism and Further Spread of Christianity

Although the Benedictine family of monks had been in existence since the sixth century, many of the older monasteries had grown wealthy and became lax in the observance of their rules. This gave rise to the spirit of reform that was to continue its influence into the twelfth century. In the year A.D. 910, the Benedictine Congregation of Cluny was established, which returned to the old observances and founded more than 300 monasteries. In 1084, St. Bruno founded the Carthusian Order, which also restored the original spirit and fervor of contemplative monasticism. The monks also engaged in agriculture and transcribed books, in addition to prayer and contemplation. In 1098, St. Robert established the Cistercian Order in the monastery at Citeaux, France. One saint who gave glory to the Cistercian Order was St. Bernard, the author of the famous prayer, the Memorare, which is still recited the world over. Because of his wisdom, St. Bernard became an adviser to the popes, settled disputes between warring cities, and preached—by order of Pope Eugene III—for the Second Crusade (1147–1149). However, the Order itself engaged mostly in missionary work. The Cistercians helped continue the Christianization of the Germanic and Slavic nations in northern Europe. St. Norbert of Xanten, a friend of St. Bernard, founded another religious order, the Premonstratensians, in 1120. The Premonstratensians followed the ideals of the Cistercian Order. However, the members were not monks but Canons Regulars, and they worked as preachers and served at parishes near their abbeys. They were also known as Norbertines, after the name of their founder. The members today usually have the title “O. Praem” (Ordo Praemonstratensis) placed after their name.

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