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
Great Recoinage of 1816 shillings weighing 87.2727 grains (or 5.655 grams), half-crowns of 218.1818 grains (14.138 grams) and crowns of 436.3636 grains (28.276 grams). Over the many reigns until decimalisation other denominations came and went, such as the threepence, sixpence, florin, and double florin, always weighing exactly one troy pound per 66 shillings (irrespective of fineness, which was reduced to 50% in 1920, and to 0% in 1947). This made 5 sterling silver shillings (which is 1 crown), about the weight of .9091 troy ounce of sterling silver. Great Recoinage of 1816 The Great Recoinage of 1816 was an attempt by the British Government