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
Troy weight the sceat with the silver penny. This coin was derived from half of a silver dirhem. The weights were then derived by a count of coins, by a mix of Charlemagne and Roman systems. A shilling was set to twelve pence, an ounce to twenty pence, and a pound to twelve ounces or twenty shillings. The penny was quite a lot of money, so weight by coins was not a general practice. Later kings debased the coin, both in weight and fineness. The original pound divided was the tower pound of 5400 grains, but a later pound of 5760 grains