Coins of the pound sterling also became known as a "pound". (240 actual pennies, however, weighed only 5400 troy grains, known as tower pound, a unit used only by mints. The tower pound was abolished in the 16th century.) The silver penny remained the primary unit of coinage for about 500 years. The purity of 92.5% silver (i.e., sterling silver) was instituted by Henry II in 1158 with the "Tealby Penny" — a hammered coin. Over the years, the penny was gradually debased until by the 16th century it contained about a third the silver content of a proper troy 24 grain pennyweight. By 1915,
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