The 9th century was a period from 801 (represented by the Roman numerals DCCCI) through 900 (CM) in accordance with the Julian calendar.

The Carolingian Renaissance and the Viking raids occurred within this period. In the Middle East, the House of Wisdom was founded in Abbasid Baghdad, attracting many scholars to the city. The field of algebra was founded by the Muslim polymath al-Khwarizmi. The most famous Islamic scholar Ahmad ibn Hanbal was tortured and imprisoned by Abbasid official Ahmad ibn Abi Du'ad during the reign of Abbasid caliph al-Mu'tasim and caliph al-Wathiq. In Southeast Asia, the height of the Mataram Kingdom happened in this century, while Burma would see the establishment of the major kingdom of Pagan. Tang China started the century with the effective rule under Emperor Xianzong and ended the century with the Huang Chao rebellions. In America, the Maya experienced widespread political collapse in the central Maya region, resulting in internecine warfare, the abandonment of cities, and a northward shift of population.

West Africa

Southeastern Nigeria

Around the 9th century, the Igbo people of what is now southern Nigeria developed bronze casts of humans, animals, and legendary creatures. These bronzes, which were used as vessels, amulets, pendants, and sacrificial tools, are among the earliest made bronzes ever found in Nigeria.