The 9th century is the period from 801 to 900 in accordance with the Julian calendar in the Christian/Common Era.
Britain experienced a great influx of Viking peoples in the ninth century as the Viking Age continued from the previous century. The kingdoms of the Heptarchy were gradually conquered and puppet rulers were given power over these. This invasion was achieved by a huge military force known as the Great Heathen Army which was supposedly led by Ivar the Boneless, Halfdan Ragnarsson and Guthrum. This Danish army first arrived in Britain in 865 in East Anglia. After taking the kingdom there the army proceeded to capture the city of York (Jorvik) and establish the kingdom of Jorvik. The Danes went on to subjugate the kingdom of Northumbria and take all but the western portion of Mercia. The remaining kingdom of Wessex was the only kingdom of the Heptarchy left. Alfred the Great managed to maintain his kingdom of Wessex and push back the Viking incursions, relieving the neighbouring kingdoms from the Danes following his famous victory over them at the Battle of Edington in 878. Alfred re-established Anglo-Saxon rule over the western half of Mercia and the Danelaw was established which separated Mercia into halves, the eastern half remaining under the control of the Danes.
Ireland was affected also by the Viking expansion across the North Sea. Extensive raids were carried out across the coastline and eventually permanent settlements were established, such as that of Dublin in 841. Particular targets for these raids were the monasteries on the western coast of Ireland as they provided a rich source for loot. On such raids the Vikings set up impermanent camps, which were called longphorts by the Irish. This period of Viking raids on the coasts of Ireland has been named the longphort phase after these particular types of settlements. Ireland in the ninth century was organised into an amalgam of small kingdoms, called tuatha. These kingdoms were sometimes grouped together and ruled by a single, provincial ruler. Providing such a ruler can establish and maintain authority over a portion of these tuatha they were sometimes granted the title of High King (see High King of Ireland).
Scotland experienced significant Viking incursions during the ninth century also. The Vikings established themselves in coastal regions, usually in northern Scotland, and in the northern isles such as the Orkneys and Shetland. The Viking invasion and settlement in Scotland provided a contributing factor in the collapse of the kingdoms of the Picts, who inhabited most of Scotland at the time. Not only were the Pictish realms either destroyed or severely weakened, the Viking invasion and settlement may have been the reason for the movement of Kenneth MacAlpin, the present king of Dál Riata, which had also been devestated by the Viking incursions. The kingdom of Dál Riata, located on the western coast of Scotland, had been destroyed after the death of their previous king Áed mac Boanta in 839, according to the Annals of Ulster, which may have made the new king Kenneth MacAlpin move to the east, and conquer the remnants of the Pictish realms. Kenneth MacAlpin became king of the Picts in 843 and later kings would be titled as the King of Alba or King of Scots.
Art of the "Dark Ages"
First and foremost, art existed because the Church required it. The basic tools of the Roman Catholic mass, thousands of golden art objects were made. Sacred cups, vessels, reliqueries, crucifixes, rosaries, altar pieces, and statues of the Virgin and Child or Saints all kept the flame of art from dying out in the period. Architecture began to revive to some extent by the 9th century. It took the form of Church facilities of all kinds, and the first castle fortifications since Roman times began to take form in simple "moat and baily" castles, or simple "strong point" tower structures, with little refinement.
- The Arab merchant Shulama wrote that Chinese junk ships could carry 600 to 700 passengers aboard for sailing missions into the Indian Ocean. He wrote that the draft of Chinese ships was too deep for entering the Euphrates River (modern-day Iraq), which forced them to land small boats on the banks of the river for passengers and cargo instead.
- An unknown event causes the decline of the Maya Classical Era.
- Beowulf might have been written down in this century, though it could also have been in the 8th century.
- Reign of Charlemagne, and concurrent (and controversially labeled) Carolingian Renaissance in Western Europe.
- Large-scale Viking attacks on Europe begin, devastating countless numbers of people.
- Oseberg ship burial.
- The Magyars arrive in what is now Hungary, taking it from Bulgaria.
- The Tukolor settle in the Senegal river valley.
- Muslim traders settle in the northwest and southeast of Madagascar.
- 800 — Charlemagne is crowned emperor of Rome by Pope Leo III.
- 800 — Arab fleet sails up the Tiber.
- 800–909 — Rule of Aghlabids as an independent Muslim dynasty in North Africa, with their capital at Tunis.
- 802 — Jayavarman II of the Khmer people in Cambodia founds the Khmer empire and establishes the Angkorian dynasty.
- 803 — Construction on the Leshan Giant Buddha in Tang Dynasty China is complete, after 90 years of rock-carving on a massive cliff-side.
- 809-817 — War between the Byzantine empire and the Bulgars.
- 811 — Battle of Pliska fought between a Byzantine force led by emperor Nicephorus I and a Bulgar army commanded by Khan Krum. Byzantines are defeated in a series of engagements, culminating with the death of Nicephorus I
- C. 813–c. 915 — Period of serious Arab naval raids on shores of Tyrrhenian and Adriatic seas.
- 814 — Charlemagne dies at Aachen.
- 827-902 — Aghlabid dynasty colonises emirates in Sicily and subsequently raids Southern Italy.
- 830 — House of Wisdom, a library and translation institute, established by al-Ma'mun, Abbasid caliph, in Baghdad to transfer the knowledge of Greeks, Persians, Indians, etc to Muslim world. Also The Compendious Book on Calculation by Completion and Balancing which is one of the book of algebra is written by Al-Khwarizmi who worked there.
- 840 — Death of Louis the Pious.
- 841 — Dublin is founded on the east coast of Ireland by the Vikings.
- 843 — The three sons of Louis the Pious reach an agreement known as the Treaty of Verdun and split the Carolingian empire into three divisions; East Francia was given to Louis the German, West Francia to Charles the Bald and Middle Francia to Lothair I.
- 845 — Buddhism is persecuted and banned in China.
- 848–852 — The west bank of the Tiber is annexed into the city of Rome. A defensive wall, commissioned by Pope Leo IV, is built around what came to be called the Leonine City.
- 850–875 — The first Norse settlers arrive on Iceland.
- 851 — The Arab merchant Suleiman al-Tajir visits the Chinese seaport at Guangzhou in southern China, and observes the manufacturing of porcelain, the Islamic mosque built at Guangzhou, the granary system of the city, and how its municipal administration functioned.
- 859 — Muslims establish the oldest university in the world, University of Al Karaouine, in Fez, Morocco
- 862 — The beginning the Rurik Dynasty in Russia
- 863 — The Chinese author Duan Chengshi describes the slave trade, ivory trade, and ambergris trade of Somalia in East Africa.
- 863–879 — Period of schism between eastern and western churches.
- 864 — Christianization of Bulgaria under Boris I
- 867 — Onward Revival of the Byzantine Empire under the Macedonian dynasty.
- 868 — Ahmad ibn Tulun breaks away from the Abbasid Caliphate and establishes the independent Tulunid dynasty.
- 870 — Prague Castle founded.
- 871-899 — Reign of Alfred the Great.
- 875–884 — Huang Chao leads an unsuccessful rebellion against the Tang Dynasty in China.
- 878 — Battle of Edington results in the victory of Alfred the Great over the Danish warlord Guthrum.
- 885 — Arrival of the disciples of SS. Cyril and Methodius, Clement of Ohrid and Naum of Preslav in Bulgaria. Development of the Cyrillic Alphabet.
- 896 — Magyars arrive in the Carpathian Basin and found an independent state, which would, during the tenth and early eleventh century, develop into the Kingdom of Hungary, which was established in 1001.
Late 9th century: Bulgaria stretches from the mouth of the Danube to Epirus and Bosnia.
- In Italy, some cities became free republics: for instance Forlì, in 889.
- The Christian Nubian kingdom reaches its peak of prosperity and military power. (Early history of Sudan).
- Harald Fairhair was victorious at the battle of Hafrsfjord, and Norway was unified into one kingdom.
- Chess reaches Japan.
- The Medieval Warm Period begins.
- Adi Sankara
- Alfred the Great
- Arnulf of Carinthia
- Basil I the Macedonian 811–886), ruled (867)–(886)
- Boris I of Bulgaria
- Empress Irene of Athens
- Clement of Ohrid
- Han Yu
- Harald I of Norway
- Huang Chao
- Kenneth I of Scotland
- Louis the Pious
- Naum of Preslav
- Saint Cyril and Saint Methodius
- Taizu of Later Liang
- Wang Kon
Inventions, discoveries, introductions
- First image of a rotary grindstone in a European source — illustration shows crank, first known use of a crank in the West (Utrecht Psalter, A.D. 843)
- First known printed book, the Diamond Sutra, printed in China using woodblock printing in 868 AD.
- Invention of gunpowder by Chinese Taoist Alchemists
- Vulgar Latin begins to devolve into various Romance languages