 This debasement meant that coins produced in 1551 had one-fifth of the silver content of those minted in 1544, and consequently the value of new testoons fell from 12d to 6d.The reason the testoon decreased in value is that unlike today, the value of coins was determined by the market price of the metal contained within them.This debasement was recognised as a mistake, and during Elizabeth's reign newly minted coins, including the testoon (now known as the shilling), had a much higher silver content and regained their pre-debasement value.