Imperial and US customary measurement systems in 1824, to take effect in 1826) and United States customary units which evolved from English Units from 1776 onwards. The earliest records of English units of measure involve the weight (and therefore the value) of Saxon coins. The penny introduced by Offa was about 20 grains (1.296 g). Edward the Elder increased the weight of the English penny to 26 grains (1.685 g), thereby aligning it with the penny of Charlemagne. By the time of the Norman Conquest (1066), it had decreased to 24 grains (1.555 g). This value was subsequently called the "pennyweight" and formed the basis of
Five Grains categories of grains. The name is typically translated as the "Five Grains" or the "Five Portions of cereal", and less often as the "Five Sacred Grains" or "Crops". Some context is important to understanding the concept, however. First, this use of "five" predates modern botanical notions and is better understood as part of the symbolic use of numbers in Chinese culture. From a very early date, Han culture understood the world as composed of five elements and many corresponding pentads were enumerated, including the Five Directions (south, north, west, east, "and" center), the Five Colors (red, black, white, "qing", and