The medieval era often is considered a time of modest achievements, literally a middle period between the substantial intellectual achievements of Greece and Rome and the Renaissance. Yet this sweeping generalization was not true for technology, which underwent great changes during these years. The decline of the Roman Empire, the emergence of the feudal system, the growing frequency of international trade, and, European exposure to the Middle East through the Crusades changed the way people lived. The Middle Ages were a period of substantial achievement in agriculture, new power sources, mechanization, military weapons, transportation, and construction. These developments so transformed technology that they produced a medieval industrial revolution.

Warfare

The introduction of the stirrup, previously known only in Asia, transformed warfare and may have helped restructure society in eighth-century Western Europe. It allowed a warrior to use a lance and...