World map in 900 AD

Border history

The interactive map lets you inspect named territories in 900 AD and compare them to earlier or later snapshots on the timeline.

Biographical context

Meet figures alive in, or close to, 900 AD and move from political geography to the people connected to the period.

Era-based reading

The related chronicles below provide long-form reading tied closely to the medieval period.

629 AD – 1180

Byzantine–Arab Wars

Byzantine Empire vs Umayyad Caliphate, Abbasid Caliphate

Centuries of warfare between Byzantium and successive Arab caliphates. The Arabs besieged Constantinople twice (674–678, 717–718) but failed both times, with Greek fire proving decisive. The frontier stabilized along the Taurus Mountains for centuries.

Key battles and events: Battle of Yarmouk (636); First Arab Siege of Constantinople (674–678)

900 AD – 1168

Toltec Wars

Toltec Empire vs Chichimec invaders, rival Mesoamerican states

The Toltec Empire, centered at Tula, dominated central Mexico through military conquest before being overthrown by Chichimec invaders — their warrior legacy deeply influenced the later Aztec civilization.

Key battles and events: Toltec conquest of central Mexico (c. 950); Fall of Tula (c. 1168)

899 AD – 955 AD

Magyar Invasions of Europe

Magyar horsemen vs Various European kingdoms

Magyar (Hungarian) horse archers raided deep into Western Europe for over half a century, reaching as far as Spain and southern France. Otto I's decisive victory at the Battle of Lechfeld ended the raids and led to Hungary's Christianisation and settlement.

Key battles and events: Battle of Pressburg (907); Battle of Lechfeld (955)

860 AD – 1240

Wars of the Kievan Rus'

Kievan Rus' princes vs Byzantine Empire, Pechenegs, Cumans, Mongols

The Rus' state expanded from Viking origins into a major European power, warring with Byzantium and steppe nomads before fracturing into rival principalities conquered by the Mongols.

Key battles and events: Siege of Constantinople (860); Sviatoslav's Balkan campaign (968–971)

802 AD – 1431

Wars of the Khmer Empire

Khmer Empire vs Champa, Dai Viet, Ayutthaya

The Khmer Empire dominated Southeast Asia from Angkor for six centuries, waging wars against Champa, Dai Viet, and eventually Ayutthaya. The Thai sack of Angkor in 1431 ended the empire and forced the capital's relocation to Phnom Penh.

Key battles and events: Cham sack of Angkor (1177); Jayavarman VII's counter-offensive (1181)

800 AD – 1000

Chichén Itzá Rise and Terminal Classic Collapse

Chichén Itzá vs Cobá vs Yaxuná vs Uxmal and the Puuc cities

During the Terminal Classic, Chichén Itzá rose to dominance in the northern Yucatán, defeating rivals such as Cobá and absorbing Puuc polities while the southern Maya lowland cities collapsed.

Key battles and events: Abandonment of Uxmal and the Puuc sites (c. 950 CE); Chichén Itzá conflict with Yaxuná (c. 900 CE)

800 AD – 1500

Mississippian Chiefdom Wars

Cahokia vs Moundville vs Etowah vs Spiro vs other Mississippian chiefdoms

Widespread warfare among the mound-building Mississippian chiefdoms of the eastern woodlands, centred on the metropolis of Cahokia — North America's largest pre-Columbian settlement.

Key battles and events: Cahokia's rise to dominance (c. 1050); Palisade construction at Cahokia (1170)

793 AD – 1066

Viking Invasions

Norse Vikings vs Anglo-Saxons vs Franks vs various kingdoms

Nearly three centuries of Norse raids, conquests, and settlements that reshaped northern Europe — from the sack of Lindisfarne to the Norman conquest of England.

Key battles and events: Lindisfarne (793); Siege of Paris (885–886)

Rayy / Baghdad / Persia

Al-Razi

c. 854 – 925

First clinical distinction of smallpox from measles, empirical medicine, alchemy, critique of Galen's humoral theory

Egypt & Babylonia

Saadia Gaon

882 CE – 942 CE

First systematic Jewish philosopher, translator of the Torah into Arabic, Gaon of Sura

Babylonia (modern Iraq)

Hai Gaon

939 CE – 1038 CE

Gaon of Pumbedita, master of Talmudic law, author of nearly one thousand responsa, last and greatest of the Geonim

Baghdad

Al-Khwarizmi

c. 780 CE – c. 850 CE

Father of algebra, originator of the word 'algorithm', pioneer of Hindu-Arabic numerals in the Islamic world

Persia / Central Asia

Ibn Sina

c. 980 CE – 1037 CE

Author of the Canon of Medicine, philosopher of the Islamic Golden Age, synthesiser of Greek and Islamic medical tradition

India (Kerala to the Himalayas)

Shankara

c. 788 CE – c. 820 CE

Founder of Advaita Vedanta, philosopher of non-dualism, unifier of Hindu thought across India

Built 900 AD · Oceania

House of Taga

Row of massive latte stone pillars on Tinian in the Mariana Islands, once supporting the elevated house of a legendary Chamorro chief.

Built 900 AD · Africa

Kilwa Kisiwani

Swahili island sultanate controlling East African gold trade

Built 900 AD · Africa

Mapungubwe

Iron Age hilltop kingdom in South Africa that predated Great Zimbabwe, famous for its golden rhinoceros figurine

Built 900 AD · Africa

Mombasa

Key Swahili coast trading port for gold, ivory, and spices

Built 900 AD · Africa

Sofala

Swahili Coast gold trade port, the primary outlet for Great Zimbabwe's gold that connected interior Africa to Indian Ocean commerce

Built 900 AD · Africa

Zanzibar

East African island at the heart of Indian Ocean trade

Rayy / Baghdad / Persia · Scientist

Al-Razi

The Physician Who Doubted Galen

The Persian physician who first distinguished smallpox from measles, distilled alcohol for medicine, wrote the largest medical encyclopedia of the ancient world, and dared to challenge the greatest medical authority in history — in his own words.

Egypt & Babylonia · Philosopher

Saadia Gaon

The Father of Jewish Philosophy

The Egyptian-born scholar who became the most formidable Jewish intellectual of the medieval world — translator of the Torah, author of the first systematic work of Jewish philosophy, and the Gaon who single-handedly stopped the fracturing of the Jewish calendar.

Babylonia (modern Iraq) · Philosopher

Hai Gaon

The Last Light of Babylon

The last and greatest of the Geonim — the scholar who answered questions from Jews across four continents, shaped the foundations of Jewish law for a millennium, and whose death in 1038 ended five centuries of Babylonian Jewish supremacy.

Baghdad · Thinker

Al-Khwarizmi

The Man Who Invented Algebra

The Baghdad scholar who gave the world algebra and the word algorithm — how a ninth-century polymath at the House of Wisdom synthesised Greek, Indian, and Persian mathematics into a system that would power every equation ever written.