1816 To 1967
For the Great Recoinage of 1816, the mint was instructed to coin one troy pound (weighing 5760 grains) of standard (0.925 fine) silver into 66 shillings, or its equivalent in other denominations. This effectively set the weight of the shilling, and its subsequent decimal replacement 5 new pence coin, at 87.2727 grains (or 5.655 grams) with a diameter of 24 mm from 1816 to 1990, when the new smaller 5p coin was introduced.
In 1920, along with other national coins, the silver content was reduced from 92.5% (sterling) to 50%, and in 1947 to pure cupro-nickel.
The shilling coin issued in most of the 20th century was virtually identical in size and weight to the German 1 Deutsche Mark coin (sufficiently similar to be interchangeable in coin-operated machines). This reflected the pre-First World War exchange rate of 20 marks to one pound; by the end of the shilling's circulation, the mark was worth six times as much.
During the reign of Elizabeth II, shillings were minted featuring both the English three lions passant coat of arms, and the Scottish lion rampant coat of arms (see illustration above). Distinct English and Scottish reverses were also a feature of shillings minted during the reign of her father George VI.
Before decimalisation, there were twenty shillings to the pound and twelve pence to the shilling, and thus 240 pence to the pound. Two coins denominated in multiple shillings were also in existence at this time. They were the florin (two shillings), which was in general circulation and adopted the value of ten new pence (10p) in 1971, and the crown (five shillings), the highest denominated non-bullion UK coin at decimalisation. The crown was not in general circulation at the time, however, being minted infrequently to commemorate important occasions (e.g. the coronation of a new monarch).
Read more about this topic: Shilling (British Coin), History