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
Penny (English coin) modern grains (1.3 to 1.5 g). It was standardized to 32 Tower grains, 1/240th of a Tower pound (approx. 350 g). The alloy was set to sterling silver of 925/1000 in 1158 under King Henry II. The weight standard was changed to the Troy pound (373.242 g) in 1527 under Henry VIII, i.e. a pennyweight became about 1.555 grams. As the purity and weight of the coin was critical, the name of the moneyer who manufactured the coin, and at which mint, often appeared on the reverse side of the coin. From the time of King Offa, the penny was