Anglo-Saxon pound × 32 = 7680 wheat grain. The Tower wheat grain was defined as exactly of a troy grain. Expressed in modern English troy grains, the Tower pound was 7680 × = 5400 modern troy grains (350 g). The Tower pound was divided into 12 ounces, each ounce into 20 pennyweights, and each pennyweight into 24 barleycorns. There were thus 480 barleycorns to a Tower ounce, 5760 barleycorns to a Tower pound of 350 g. The Anglo-Saxon pound (Saxon pound, moneyers' pound or Tower pound) remained in use for silver and gold coinage in England after the adoption of the medieval
Troy weight Congress on May 19, 1828. The British Imperial troy ounce (known more commonly simply as the imperial troy ounce) was based on, and virtually identical with, the pre-1824 British troy ounce and the pre-1707 English troy ounce. (1824 was the year the British Imperial system of weights and measures was adopted, 1707 was the year of the Act of Union which created the Kingdom of Great Britain.) Troy ounces have been used in England since about 1400 and the English troy ounce was officially adopted for coinage in 1527. Before that time, various sorts of troy ounces were in use