Religion & Belief in the 9th century

194 sourced entries, 800 CE to 899 CE, oldest first. Also see Religion & Belief across every century or everything else in the 9th century.

800December 25 – Charlemagne, king of the Franks, is crowned Holy Roman Emperor by Pope Leo III as Charles I, with the title "Emperor of the Romans". The coronation takes place during Mass at the Basilica of St. Peter in Rome, on Christmas Day. The Frankish Empire is formed in Western Europe, which is not recognized by Empress Irene at Constantinople. This triggers a series of disputes with the Byzantines around who is officially ruling the former Western Roman Empire.source
800Archbishop Hygeberht of Lichfield retires; he is succeeded by Ealdwulf. King Coenwulf of Mercia is on better terms with the archbishopric of Canterbury than his predecessor, and unsuccessfully attempts to have the Mercian archiepiscopal see transferred to London (approximate date).source
800The Book of Kells is written and illuminated in a Columban monastery, in Ireland (approximate date).source
801Rabanus Maurus, Frankish Benedictine monk, takes his vows in the monastery of Fulda and receives ordination as a deacon.source
801A synod appears to have been held at Chelsea, as an extant charter (Sawyer 158) records a confirmation of a land grant by Coenwulf, the king of Mercia that was part of the council's proceedings.source
802October 31 – Empress Irene is deposed after a 5-year reign, and banished to Lesbos. High-ranking patricians place Nikephoros, the minister of finance (logothetes tou genikou), on the throne. He is crowned in the Hagia Sophia at Constantinople, by Patriarch Tarasios, as emperor of the Byzantine Empire.source
802The Mecca Protocol: Caliph Harun al-Rashid and the leading officials of the Abbasid Caliphate perform the hajj to Mecca, where the line of succession is finalized. Harun's eldest son al-Amin is named heir, but his second son al-Ma'mun is named as al-Amin's heir, and ruler of a broadly autonomous Khurasan. A third son, al-Qasim, is added as third heir, and receives responsibility over the frontier areas with the Byzantine Empire.source
802The Haeinsa Temple of the Jogye Order is built in Korea.source
802The Vikings plunder the treasures of Iona Abbey, on the west coast of Scotland (approximate date).source
803October 12 – The Synod of Clofesho (possibly Brixworth) is held, at which the Archbishopric of Lichfield is demoted to an ordinary bishopric, with papal permission obtained by King Coenwulf of Mercia.source
803November - December: Caliph Harun al-Rashid marries Umm Muhammad, the daughter of Abbasid prince Salih al-Miskin and Umm Abdullah, the daughter of Isa ibn Ali, in Al-raqqah. She had formerly been married to Ibrahim ibn al-Mahdi, who had repudiated her.source
803Caliph Harun al-Rashid has his friend and vizier (secretary) Ja'far ibn Yahya beheaded, The surviving members of the influential Barmakid family (Jafar's family) are imprisoned on the orders of Harun, and their property is confiscated.source
804Ludger, Frisian missionary, becomes the first bishop of Münster, and builds a monastery there.source
804The Inscription of Sukabumi from Eastern Java marks the beginning of the Javanese language.source
804Priest Saichō, patriarch of Tendai Buddhism, visits China and reportedly brings back tea seeds (or 805).source
804Abbasid caliph Harun al-Rashid marries Abbasa, the daughter of Abbasid prince and official Sulayman.source
805Priest Saichō, patriarch of Tendai Buddhism, visits China and introduces tea to Japan on his return (or 804).source
805The Palatine Chapel in Aachen (modern Germany) is consecrated by Pope Leo III.source
806April 12 – Nikephoros I is elected patriarch of Constantinople, succeeding Tarasios.source
806July 26 – Wulfred is elected Archbishop of Canterbury.source
806The church (oratory) in Germigny-des-Prés is built by Bishop Theodulf of Orléans.source
806King Eardwulf of Northumbria is expelled from his kingdom by his rival Ælfwald II, who takes the throne. Eardwulf flees to the Frankish court of Charlemagne, and later visits Pope Leo III in Rome.source
806Harun al-Rashid appoints Ashot Msaker ("the Carnivorous") as the new presiding prince of Armenia. The Bagratids emerge as one of the country's two most powerful noble families. Harun recognizes another Bagratid branch, under Ashot I Curopalates, as princes of Caucasian Iberia.source
806Hōzen-ji Temple is founded in Wakakusa, Nakakoma District, Japan (now Minami-Alps, Yamanashi Prefecture). The temple follows the Shingon sect of Japanese Buddhism.source
807The Jame' Atiq Mosque of Qazvin is constructed in Qazvin (modern Iran), by the orders of Harun al-Rashid.source
807The Temple of Motoyama-ji in Mitoyo (Japan), of the Kōyasan Shingon-shū sect, is constructed by the orders of Emperor Heizei.source
807The Book of Armagh is written by the Irish illuminator Ferdomnach, a scribe at the School of Armagh.source
807Emperor Nikephoros I is forced to sue for peace, on condition of paying 50,000 nomismata to Caliph Harun al-Rashid, and agrees to a yearly tribute. Nikephoros promises not to rebuild the dismantled forts. Rashid recalls his forces from various sieges, and evacuates Byzantine territory.source
808Exiled king Eardwulf of Northumbria is able to return to his kingdom, with the support of Charlemagne and Pope Leo III. He ousts the usurper, King Ælfwald II.source
809Council of Aachen (809): Frankish bishops adopt the filioque addition in the Creed. Pope Leo III intervenes, and refuses to recognize it as valid.source
810The Book of Kells (also known as the Book of Colomba), an illuminated manuscript, is completed by Celtic monks (approximate date).source
810Tikal Temple III, also known as the Temple of the Jaguar Priest, is constructed in Tikal National Park (modern Guatemala).source
811October 2 – Michael I is declared emperor of the Byzantine Empire; Stauracius is forced by senior officials to retire to a monastery.source
811Fourth Fitna: Abbasid caliph al-Amin appoints Ali ibn Isa ibn Mahan as governor of Khurasan, in northeast Persia, and sends an army of 40,000 men with him against his half-brother al-Ma'mun. Ibn Mahan's army is defeated by a smaller army under Tahir ibn Husayn, at Rayy. During the fighting Ali ibn Isa ibn Mahan is killed.source
813July 11 – Michael I, under threat by conspiracies, abdicates in favor of his general Leo the Armenian, and becomes a monk (under the name Athanasius). His sons are castrated to prevent them succeeding the Byzantine throne, and relegated into monasteries. One of them, Niketas (renamed Ignatius), eventually becomes a patriarch of Constantinople.source
813Caliph al Ma’mun founds a school in Baghdad called the House of Wisdom. In this school scholars translated Greek philosophy classics into Arabic.source
813Third Council of Tours: Priests are ordered to preach in the vernacular language (either Vulgar Latin or German).source
814Louis I establishes himself at the imperial court of Aachen. He appoints Benedict of Aniane as his chief advisor on religious matters, and makes him abbot of Kornelimünster Abbey, which is founded by him.source
814Byzantine Iconoclasm: Conflict erupts between Emperor Leo V and Patriarch Nikephoros, on the subject of iconoclasm. The latter is excommunicated.source
815Synod of Constantinople: A council led by patriarch Theodotus I, in the Hagia Sophia, reinstitutes iconoclasm.source
816October 5 – King Louis the Pious (son of Charlemagne) is crowned emperor of the Holy Roman Empire, by Pope Stephen IV at Reims. He also crowns the emperor's wife Ermengarde as Holy Roman Empress. The ceremony in Reims re-establishes the principle of papal supremacy, by recognising the importance of the pope in imperial coronations. Louis gives the pope many gifts, including the estate tax Vendeuvre, near Troyes (Northern France).source
816Synod of Aachen: Louis the Pious calls for a council about the regulations (Institutio canonicorum Aquisgranensis) for monastic life in the Frankish Empire.source
816Synod of Chelsea: King Coenwulf of Mercia calls for a council about his right to appoint abbots and monasteries in England.source
817Synod of Aachen: The council adopts a capitulare monasticum, containing the Benedictine rules of monastic life in the Frankish realm.source
818April 17 – King Bernard of Italy, illegitimate son of Pepin of Italy, is tried and condemned to death by Emperor Louis I. The Kingdom of Italy is reabsorbed into the Frankish Empire.source
818Theodulf, bishop of Orléans, is deposed and imprisoned, after becoming involved in a conspiracy with Bernard of Italy.source
819August 11 – Caliph Al-Ma'mun returns to Baghdad, securing the city's place as the capital of the Abbasid Caliphate.source
819Abbasid caliph Al-Ma'mun dismisses Al-Hasan ibn Sahl as governor of al-Iraq.source
819Nominoe, a noble Briton, is appointed by Louis I as count of Vannes in Brittany (approximate date).source
820Caliph Al-Ma'mun appoints Ibrahim al-Ifriqi as Abbasid governor of Yemen. He remains in office until 821.source
820Abbasid caliph Al-Ma'mun appoints Isa ibn Yazid al-Juludi as Abbasid governor of Yemen, for a few months.source
820Caliph Al-Ma'mun appoints Hisn ibn al-Minhal as Abbasid governor of Yemen, for a few months.source
820Caliph al-Ma'mun appoints Abu Nasr ibn al-Sari as Abbasid governor of Egypt.source
821Byzantine general Thomas the Slav leads a revolt, and secures control over most of the Byzantine themes (provinces) in Anatolia. He gets recognition from the Abbasid Caliphate, and concludes a peace treaty with Caliph al-Ma'mun. Thomas crosses with his fleet from Abydos to Thrace, and blockades Emperor Michael II in Constantinople; but Thomas' first attack on the capital fails.source
821Caliph Al-Ma'mun appoints Nu'aym ibn al-Waddah al-Azdi as the governor of Yemen.source
821Tahir ibn Husayn, an Iranian general, is appointed as governor of Khurasan, as a reward for supporting the Abbasid caliph al-Ma'mun in the Fourth Fitna.source
821By the time Al-Ma'mun becomes caliph, the Arabs and the Byzantines have settled down into border skirmishing, with Arab raids deep into Anatolia to capture booty.source
822Emperor Louis I performs public penance for causing his nephew Bernard's death 4 years earlier, at his palace of Attigny (Ardennes), before Pope Paschal I, and the Frankish nobles (this to restore harmony and re-establish his authority).source
822The earliest known mention of the Serbs, in Einhard's Royal Frankish Annals.source
823April 5 – Lothair I, eldest son of Emperor Louis I, is crowned co-emperor again by Pope Paschal I at Rome (initiating the papal practice of handing the imperial sword over, as a symbol of temporal power in the Holy Roman Empire).source
823King Ceolwulf I of Mercia is deposed by Beornwulf, who takes the throne of Mercia. During his rule he rebuilds the Abbey of St. Peter, and presides over two synods at Clofesho.source
824June 4 – Pope Eugene II is selected by church leaders and the local nobility of the Papal States as the 99th Pontiff of the Roman Catholic Church, succeeding Pope Paschal I, receiving a majority after the more conservative Zinzinnus is rejected.source
824November 11 – The Constitutio Romana, drawn up between King Lothair I of Italy, Louis the Pious, since 817, and Pope Eugene II, establishes the authority of the Holy Roman Emperors over the papacy of Rome.source
824Zenpuku-ji, one of the oldest Tokyo temples, is founded by the Japanese Buddhist monk Kūkai.source
825Murcia is founded by the emir of Cordoba Abd ar-Rahman II.source
825A group of Persio-Assyrian adherents of the Church of the East, under the leadership of two Persian bishops Prod (or Proth, also known as Aphroth) and Sappor (also known as Sabrisho), reach Kerala, India and reside in Quilon.source
825Borobudur, a Mahayana Buddhist Temple, is completed in Central Java (modern Indonesia).source
827Khalid ibn Abd al-Malik al-Marwarrudhi and Ali ibn Isa al-Asturlabi travel to the Plain of Sinjar (modern Iraq), under orders of Caliph Al-Ma'mun, to measure the size of the Earth.source
828Alcamo in Sicily is founded by the Muslim commander al-Kamuk (approximate date).source
828At the instigation of Adalram, archbishop of Salzburg, the first Christian church in Central and Eastern Europe is built in Nitra, Pannonia.source
829Ansgar, Frankish abbot of Corvey (modern Westphalia), is appointed missionary to Sweden by Louis the Pious, at the request of the Swedish king Björn at Haugi.source
830Hirsau Abbey (modern Germany) is founded by the Rhenish Franconian count Erlafried of Calw (approximate date).source
831Ansgar is consecrated; he travels to Rome to receive the pallium from Pope Gregory IV.source
831Nominoe, duke of Brittany, is designated missus imperatoris (imperial emissary) by Louis the Pious, at Ingelheim (modern Germany).source
831Summer – Ansgar, Frankish missionary, founds the first church at Birka (modern Sweden).source
832The second St. Mark's Basilica in Venice (replacing an older church at a different location) is built, and becomes one of the best known examples of Italo-Byzantine architecture.source
832Emperor Theophilos promulgates a new edict against the usage of icons in the Byzantine Empire. He establishes strict punishments against idolators, and persecutes violators.source
832The town of Clondalkin (modern Ireland) is sacked by Vikings from Denmark, and the monastery is burnt to the ground.source
833Ibn Hisham, Muslim historian, collects oral traditions that form the basis for the biography of the Islamic prophet Muhammad.source
835November 1 – Pope Gregory IV promotes the celebration of the feast of All Saints on this day throughout the Frankish Empire.source
836Driven by tensions between his favoured Turkish guard and the populace of Baghdad, Abbasid caliph al-Mu'tasim moves his residence to the new city of Samarra, 130 km north of Baghdad. With brief interruptions, the city will remain the seat of the Abbasid caliphs until 892.source
837Byzantine–Arab War: Emperor Theophilos leads a massive Byzantine expeditionary force into Mesopotamia. He sacks the cities Arsamosata and Sozopetra — which some sources claim as the birthplace of Abbasid caliph Al-Mu'tasim — and forces Melitene to pay tribute.source
838January – Babak Khorramdin, an Iranian military leader, is brutally executed by order of al-Mu'tasim.source
838Possible conversion of some Khazars to Judaism (approximate date).source
839May 20 — Thirteen months before his death, Louis the Pious, successor to his father Charlemagne, consents to the division of Charlemagne's empire among his sons in a declaration at Worms. Upon Louis I's death in 840, Lothair (age 45) is devised Middle Francia that includes Switzerland and northern Italy; Louis the German (Louis II), age 36, receives Eastern Francia that includes much of Germany; and Charles the Bald (17) gets West Francia that incorporates most of France.source
839The first official mention of Andorra is recorded, in the manuscripts of the cathedral at La Seu d'Urgell (modern Spain).source
840Nobis becomes bishop of St. David's, in the Welsh Kingdom of Dyfed (approximate date).source
841Summer – Vikings sail up the River Seine and devastate the city of Rouen in Normandy. They burn the Benedictine monastery of Jumièges Abbey; 68 captives are taken, and returned on payment of a ransom, by the monks of St. Denis.source
842February 19 – The Medieval Iconoclastic Controversy ends, as a council in Constantinople formally reinstates the veneration of icons in the churches.source
842Abbasid caliph Al-Wathiq appointed his brother, Jaʽfar ibn Muhammad al-Mutasim (future al-Mutawakkil) as Leader of Hajj in 842.source
842Vikings attack the Irish monastery at Clonmacnoise from bases in Ireland.source
844June 15 – Louis II, eldest son of Emperor Lothair I, is crowned king at Rome by Pope Sergius II, and becomes co-ruler of Middle Francia, and over Lombardy, Friuli, and Tuscany in Italy.source
845March 6 – 42 captured Byzantine officials from Amorium are executed at Samarra, then the capital of the Abbasid Caliphate, after they repeatedly refuse attempts to convert them to Islam.source
845Great Anti-Buddhist Persecution: Emperor Wu Zong begins the persecution of Buddhists and other foreign religions in China, such as Zoroastrianism, Nestorian Christianity and Manichaeism. More than 4,600 monasteries, 40,000 temples and numerous shrines are destroyed. More than 260,000 Buddhist monks and nuns are forced to return to secular life.source
845John Scotus Eriugena, Irish theologian, travels to France and takes over the Palatine Academy in Paris, at the invitation of Charles the Bald (approximate date).source
846Muslim forces attempt to raid Rome but only pillage the countryside around the city before being beaten back by Duke Guy I of Spoleto. In the aftermath, Pope Leo IV starts walling the area around the Vatican hill, creating the Leonine City.source
847April 10 – Leo IV is consecrated 103rd pope of Rome (where he was born c.790). Because of the sense of urgency driven by the previous year's Arab raid against Rome, he is consecrated without waiting for the consent of the Holy Roman Emperor. He will reign until 855.source
848Pope Leo IV builds (on the opposite of the Tiber River) the Leonine City, a fortified three-kilometre wall that encircles the Vatican Hill and Borgo, to defend Rome.source
848Summer – Bordeaux, capital of Aquitaine, falls into the hands of Viking raiders. King Charles the Bald sends a Frankish fleet to lift the siege. Despite destroying some Viking longships on the Dordogne River, they fail to save the city. The Abbey of Saint-Pierre in Brantôme is sacked.source
848The Roman Catholic church of Santa María del Naranco, on the slope of Monte Naranco (Northern Spain), is completed.source
850April 22 – Gunther becomes archbishop of Cologne (modern Germany).source
850June 18 – Perfecto, a Christian priest in Muslim Córdoba, is executed (beheaded) after he refuses to retract critical comments he made about Muhammad.source
850The Pillar of Eliseg is erected by King Cyngen ap Cadell of Powys (Wales), as a memorial to his great-grandfather Elisedd ap Gwylog (or Eliseg) (approximate date).source
850King Louis II, the eldest son of Lothair I, is crowned joint emperor by Pope Leo IV at Rome, and becomes co-ruler of the Middle Frankish Kingdom.source
850The Abbasid caliph al-Mutawakkil issues a decree that orders Jews and Christians to wear the zunnar, honey-coloured outer garments and badge-like patches on their on their servants' clothing.source
851September – King Pepin II of Aquitaine is captured by the forces of Count Sans II Sancion, and handed over to Charles the Bald. He is detained in the monastery of Saint Medard in Soissons.source
851The Great Mosque of Samarra (modern Iraq) is completed during the reign of Caliph Al-Mutawakkil.source
852Gandersheim Abbey in Lower Saxony (modern Germany) is founded by Duke Liudolf of Saxony.source
853The Fraumünster Church in Zürich (modern Switzerland) is founded by Louis the German.source
853Viking marauders in Gaul sail eastward from Nantes without opposition, and reach Tours. The monasteries at Saint-Florent-le-Vieil and Marmoutier are ravaged.source
855Æthelwulf grants churches in Wessex the right to receive tithes. He gives one-tenth of his lands to the Church.source
855The Slavic alphabet is created by Saints Cyril and Methodius.source
856March 15 – Emperor Michael III overthrows the regency of his mother Theodora. He appoints his uncle Bardas as the de facto regent and co-ruler of the Byzantine Empire.source
856October 1 – King Æthelwulf of Wessex marries the 12- or 13-year-old Judith, daughter of Charles the Bald, at Verberie (Northern France). She is crowned queen and anointed by Hincmar, archbishop of Reims. The marriage is a diplomatic alliance between Wessex and the West Frankish Kingdom.source
857Emperor Michael III, under the influence of his uncle Bardas, banishes his mother Theodora to the Gastria Monastery. Bardas, the de facto regent, becomes the most powerful person in the Byzantine Empire.source
857A Danish Viking fleet raids the cities of Dorestad, Paris and Orléans. Others sail up the Oise River, ravaging Beauvais and the abbey of Saint-Germer-de-Fly (approximate date).source
858October 23 – Ignatios I, patriarch of Constantinople, is imprisoned by orders of Emperor Michael III, and replaced by the layman Photius I.source
858Synod of Quierzy: The bishops remain loyal to Charles the Bald during the invasion of his dominions by Louis the German. They address a conciliatory letter to Louis the German, which includes the False Decretals.source
858Viking raiders, led by Björn Ironside, set fire to the earliest church on the site of Chartres Cathedral. Charles the Bald pays him tribute (Danegeld) to save Verberie (Northern France).source
860Michael I succeeds Sophronius I, as patriarch of Alexandria.source
860Lusterware tiles, that decorated the mihrab of the Mosque of Uqba at Kairouan (modern Tunisia), are made (approximate date).source
861December 11 – Caliph al-Mutawakkil is assassinated by his Turkish guard, starting the period of troubles known as the "Anarchy at Samarra" (861–870). He is succeeded by his son Al-Muntasir, as ruler of the Abbasid Caliphate.source
861Spring – The Council of Constantinople, attended by 318 fathers and presided over by papal legates, confirms Photius the Great as patriarch, and passes 17 canons.source
862Ashot I ("the Great") is recognized as the 'Prince of Princes' of Armenia, by the Abbasids.source
862King Lothair II of Lotharingia tries to divorce his wife Teutberga, on trumped-up charges of incest. With the support of his brother, Louis II, the bishops give him permission to remarry during a synod at Aachen.source
862Constantine the Philosopher (alias Saint Cyril) invents the 42-letter Slavonic alphabet (Cyrillic script) as a tool for converting the Moravians to Christianity (approximate date).source
862During the Council of Shirakavan representatives of the Armenian, Byzantine and West-Syrian Churches convenes to discuss church union. Though this is not achieved, an agreement is formulated which allows for the peaceful co-existence of Orthodox and non-Chalcedonians in the Byzantine-Armenian borderlands.source
863Nicholas I excommunicates Patriarch Photios I of Constantinople.source
863The Christianization of Kievan Rus begins, ceasing the 63-year-long dominance of the Rus' Khaganate (approximate date).source
863Pope Nicholas I sends archbishops Gunther and Theotgaud to a synod of Metz, which confirms the permission given to King Lothair II of Lotharingia to remarry.source
864Spring – Emperor Louis II (the Younger) marches with a Frankish army against Rome. While en route to the papal city, he becomes ill, and decides to make peace with Pope Nicholas I.source
864The Christianization of Bulgaria begins: Boris I, Knyaz of the Bulgarian Empire, is converted to Orthodox Christianity. His family and high-ranking dignitaries accept the Orthodox faith at the capital, Pliska - from this point onwards the rulers of the Bulgarian Empire are known as ‘Tsars’ rather than ‘Khans’.source
865Caliphal Civil War: An armed conflict starts between the rival Muslim caliphs al-Musta'in and al-Mu'tazz. They fight to determine who takes control over the Abbasid Caliphate (until 866).source
865King Lothair II, threatened with excommunication, takes back his first wife, Teutberga. She expresses her desire for an annulment, but this is refused by Pope Nicholas I.source
866October 17 – Caliph al-Musta'in is put to death, after a 4-year reign. He is succeeded by al-Mu'tazz, who becomes the youngest Abbasid caliph to assume power.source
866Pope Nicholas I forbids the use of torture in prosecutions for witchcraft (approximate date).source
866Pope Nicholas I orders that all Catholics should abstain from eating the "flesh, blood, or marrow" of warm-blooded animals on Wednesdays and Fridays.source
867September – Photius I ("the Great"), patriarch of Constantinople, is removed from office and banished. Ignatius is reinstated as patriarch by Basil I.source
867The Council of Constantinople is held (presided over by Patriarch Photius), which anathematizes the use of the Filioque clause in the Creed, and also Pope Nicholas I, for his attacks on the work of Greek missionaries in Bulgaria.source
868September 15 – Ahmad ibn Tulun, a Turkish general, is sent to Egypt as governor, by the Abbasid caliph Al-Mu'tazz. He becomes the founder of the Tulunid Dynasty (until 905), and Egypt becomes an autonomous state for the first time since the Ptolemaic Kingdom.source
868Ratramnus, a Frankish monk and abbot of Corbie Abbey, writes Contra Graecorum Opposita.source
869October 5 – The Fourth Council of Constantinople, called by Basil I and Pope Adrian II, opens. The council will condemn Photius I and depose him as patriarch, reinstating his predecessor Ignatios.source
869The last monument ever erected at Tikal, Stela 11, is dedicated by ruler (ajaw) Jasaw Chan Kʼawiil II.source
870February 28 – The Fourth Council of Constantinople ends. The Bulgarians are granted an autocephalous archbishopric. with its seat in the capital of Pliska.source
870June 21 – Caliph Al-Muhtadi is deposed and killed by the Turks, after a brief reign. He is succeeded by Al-Mu'tamid (son of the late Al-Mutawakkil) as ruler of the Abbasid Caliphate, who moves his court to Baghdad. End of the Anarchy at Samarra.source
871The Cairo Genizah, a collection of Jewish manuscript fragments, is written (approximate date).source
873Azugitin, Abbasid caliph Al-Mu'tamid appointed Azugitin as governor of Mosul with deputies.source
874March 13 – The remains of Saint Nikephorus I are interred in the Church of the Holy Apostles, in Constantinople.source
874Muhammad al-Mahdi, the child of the eleventh Shi'i Twelver Imam Hasan al-Askari, begins his Imamate. His first period of occultation, known as the Minor Occultation, also begins (ends 941 CE).source
874The monastery of Sevanavank, located on the shore of Lake Sevan (Armenia), is founded.source
875December 29 – King Charles the Bald, supported by Pope John VIII, travels to Italy. He receives the Imperial Regalia at Pavia, and is crowned Holy Roman Emperor as Charles II at Rome.source
875Bretons begin to flee the land, seeking the relative security of Britain. Vikings loot the Abbey of Saint-Melaine at Rennes (approximate date).source
875The construction of the Great Mosque of Kairouan is completed by Ibrahim II. He builds another three bays, reducing the size of the courtyard.source
876June – Synod of Ponthion: Charles II summons a council, in which a papal brief is read from Pope John VIII. He appoints Ansegisus as papal legate and primate over Gaul, in the West Frankish Kingdom.source
878April 16 – The city of Belgrade is first mentioned in a papal letter to Boris I, ruler (khan) of the Bulgarian Empire.source
878September 7 – Pope John VIII crowns Louis the Stammerer as king of the West Frankish Kingdom, in the cathedral at Troyes.source
878The excommunication of Formosus is lifted, after he has promised never to return to Rome. He will become Pope in 891.source
878Poorna, the illegitimate grand-daughter of Shankara, unifies all of his teaching in the Upadeśasāhasrī.source
879June 7 – Pope John VIII recognizes the Duchy of Croatia, under Duke (knyaz) Branimir, as an independent state.source
879Wilfred the Hairy, count of Barcelona, founds the Benedictine monastery at Ripoll, in Catalonia (Spain).source
879Fourth Council of Constantinople: Emperor Basil I calls for a synod, and reinstates Photius I as patriarch of Constantinople.source
880May 1 – The Nea Ekklesia is inaugurated in Constantinople, by Patriarch Photius I, setting the model for all later cross-in-square Orthodox churches.source
880Pope John VIII issues the bull Industriae Tuae, creating an independent ecclesiastical province in Great Moravia, with archbishop Methodius as its head. Old Church Slavonic is recognized as the fourth liturgical language, besides Latin, Greek and Hebrew.source
880The first known Christian bishopric in Slovakia is established in the city of Nitra, with Wiching as bishop.source
881February 12 – King Charles the Fat, the third son of the late Louis the German, is crowned as Holy Roman Emperor by Pope John VIII at Rome.source
881Bakong, the first temple mountain of sandstone, is constructed by rulers of the Khmer Empire (modern Cambodia) at Angkor.source
882December 16 – Pope John VIII is assassinated at Rome after a 10-year reign, probably the victim of a political conspiracy. He is succeeded by Marinus I, as the 108th pope of the Catholic Church.source
882December – Ishaq ibn Kundaj, a Turkic military leader, arrests the Abbasid caliph Al-Mu'tamid, when the latter (and his followers) try to flee into Tulunid territory.source
883Spring – Viking raiders ravage Flanders, and sack the abbey at Saint-Quentin. King Carloman II blocks their passage at Laviers, which had been on the banks of the Somme. Meanwhile, Vikings enter the Rhine, but are turned back by Henry of Franconia (possibly a margrave of Saxony). They over-winter at Duisburg.source
884Fall – The Arabs sack the abbey of Monte Cassino in two raids (September and November). The bulk of the monastic community flee to Teano (Campania).source
885King Alfred the Great summons Asser, a relative of Bishop Nobis of St. David's, to the English royal court. He agrees to spend six months of the year in the king's service. Asser helps to negotiate the recognition of Alfred, as overlord of the Welsh kings.source
886December – Emperor Leo VI dismisses Patriarch Photius I, who has been his tutor, and replaces him with his own brother Stephen I.source
886The Glagolitic alphabet, devised by Cyril and Methodius, missionaries from Constantinople, is adopted in the Bulgarian Empire.source
887February 5 – Theodosius Romanus ascends as Syriac Orthodox patriarch of Antioch.source
887December 26 – In an assembly at Pavia (Northern Italy), the lords of Lombardia elect Berengar I, a grandson of former emperor Louis the Pious (through his daughter Gisela), as king of Italy. He is crowned with the Iron Crown of Lombardy. After the deposition of Charles the Fat, the nobility chooses Ranulf II as duke (or 'king') of Aquitaine.source
888The Aghlabids issue decrees according to which Jews and Christians are to wear a patch (ruq'a) of white fabric on their shoulder of their outer garment, with the patch for Jews depicting an ape and that for the Christians depicting a pig.source
888Shaftesbury Abbey is founded by King Alfred the Great in Dorset. He installs his daughter Æthelgifu as first abbess (approximate date).source
889Bongwon Temple, located in Seoul (modern South Korea), is founded by the Korean Buddhist master Doseon.source
889Guy III, duke of Spoleto, defeats the Lombard king Berengar I at the Trebbia River, and is acclaimed as king of Italy at an assembly in Pavia. After confirming some privileges to the Catholic Church, he is crowned with the Iron Crown of Lombardy, by Pope Stephen V. Berengar is forced to retreat to Verona; Guy does not pursue him into Friuli, because of the (possible) wrath of King Arnulf of Carinthia.source
890King Alfred the Great begins to commission and undertake a series of translations into Old English, beginning with his own version of Pope Gregory the Great's Pastoral Care.source
891February 21 – Guy III, duke of Spoleto, is crowned Holy Roman Emperor by Pope Stephen V. His son Lambert is proclaimed king of Italy, at the capital of Pavia in Lombardy.source
893King Yasovarman I (called the Leper King) of the Khmer Empire (modern Cambodia) dedicates the Lolei Temple of the Roluos group to the god Shiva and the royal family.source
893Council of Preslav: The Byzantine clergy is expelled from Bulgaria, and the Greek language is replaced with Old Bulgarian (also known as Old Church Slavonic), as an official language.source
893The 13-year-old Charles III (the Simple), the posthumous son of Louis the Stammerer, is crowned king of the West Frankish Kingdom at the Reims Cathedral—though he is not recognized as such by King Odo (or Eudes) until 898.source
893Spring – Caliph Al-Mu'tadid recognizes Khumarawayh as autonomous emir over Egypt and Syria, in exchange for an annual tribute of 300,000 dinars. The Jazira provinces of Diyar Rabi'a and Diyar Mudar are returned to the Abbasid Caliphate. Muslim forces recover direct control of Mosul (modern Iraq) from the Shayban.source
893Asser, bishop of Sherborne, writes his Life of King Alfred in Wessex. He studies for 6 months each year in Alfred's household.source
895Hamdan ibn Hamdun, a Taghlibi Arab chieftain, is defeated and captured by Caliph Al-Mu'tadid at the fortress of Mardin (near modern Cizre). Hamdan's son Husayn enters Abbasid service, beginning the rise of the Hamdanid Dynasty.source
897January – The Cadaver Synod: Lambert II orders Stephen VI to exhume the nine-month-old cadaver of former pope Formosus, to redress him in papal robes, and have him put on trial while seated in a chair at St. Peter's. Formosus is 'convicted' of several crimes, his fingers of consecration are cut off, and the body is stripped of his vestments.source
89715 March – Al-Hadi ila'l-Haqq Yahya enters Sa'dah and founds the Zaydi Imamate of Yemen.source
897August – Stephen VI is removed from office, imprisoned and strangled in his cell. He is succeeded by Romanus as the 114th pope of the Catholic Church.source
897Caliph al-Mu'tadid recovers control of the Cilician Thughur (southeastern Anatolia) and of northern Syria, during the turmoil in the Tulunid government (approximate date).source
898January – Pope John IX is consecrated, and succeeds Theodore II, as the 116th pope of the Catholic Church. His rival Serguis III (a Spoletan ally of Lambert II) is excommunicated, and takes refuge at the court of Adalbert II.source
898John IX holds councils at Rome and Ravenna to rehabilitate the late Pope Formosus. He condemns the Cadaver Synod of the late Pope Stephen VI, and restores the clergymen who were deposed by Stephen's faction.source
899Regino of Prüm, a Benedictine churchman, is expelled from Prüm and becomes abbot of St. Maximin's Abbey (which is destroyed by the Vikings) in Trier.source