Astronomy

Machu Picchu, built in Peru by the Inca civilization, contains an "astronomical altar," used to location exact positions of the Sun and Moon. See also 1450 bce Construction; 829 Astronomy.

The phonetic script called kana is developed for writing Japanese. The simplified script is much easier to learn than Chinese ideograms, and women as well as men become literate -- resulting in the women of the next couple of centuries writing some of the great works in the Japanese language, notably Tale of Genji by Lady Murasaki.

The Anasazi begin to construct the first of the multistory apartment dwellings for which they are famous; built with masonry walls more than 1 m (3 ft) thick, the pueblos, as the Spanish later name them, contain dozens of families. See also 750 Construction.

Using water from the Gila and Salt rivers, the Hohokam of what is now Arizona construct by this time one of the most extensive irrigation networks of dams and canals in the Americas. See also 550 Construction; 1209 Transportation.

The rigid horse collar in which the main load is on the chest and skeletal system of the horse is introduced in Europe, roughly a thousand years after its first use in China. The evidence for this is that horse collars are shown on the Bayeux Tapestry showing scenes in France and England in 1066 (probably woven before 1092). See also 110 bce Transportation.

During the Tang dynasty in China, stoneware pottery is made, and perhaps an early form of porcelain, a hard translucent white ceramic from fine clay, is invented. See also 200 ce Materials; 1100 Materials.

A predecessor of the blast furnace is used for making cast iron in Scandinavia. See also 695 Construction; 1200 Materials.

The ancestor of paper money is in use in China, essentially as bank drafts on money deposited that can be exchanged for hard cash at a later date or at a different bank. See also 600 Communication; 812 Materials.

The decimal system is introduced by the Arabs into Spain. See also 1030 Mathematics.

A complete translation of Euclid's Elements is made into Arabic. See also 300 bce Mathematics; 1142 Mathematics.

Chinese mathematicians use the method of finite differences to solve equations. This is an iterative process that provides approximate solutions that can be as close as is needed to the actual solution. See also 628 Mathematics; 1209 Mathematics.