Answer:
The Sovereign coin started as a denomination of the old redundant predecimal British currency system and dates back to the time of Henry VII, but is still being minted today.
The Sovereign was not used much outside Britain other than by Britain's colonies prior to them having their own currencies, such as Australia, New Zealand and others.
The name "Sovereign" comes from the magnificent appearance and size of the coin.
The Sovereign was made from gold of varying weight and purity over the years, until the Great Recoinage Law of 1816 when the gold content was fixed to 7.322 grams, at which it currently remains.
A Sovereign coin represented One Pound or 20 Shillings or 240 Pennies in the old currency.
Variants of the Sovereign minted at different times includes the Five Sovereign, Double Sovereign, Half-Sovereign and Third-Sovereign coins. In 2009, a Quarter Sovereign coin was produced for the first time.
At Britains conversion to decimal currency in February, 1971, the Sovereign remained at the face value of One Pound, or 100 Pence in the new currency.
Current Sovereigns weigh in at 7.9881 grams, are 1.52 mm thick, have a diameter of 22.05 mm, fineness is 22 carat or 91.67% gold, and the gold content is 7.3224 grams.
These days, the Sovereign is minted as a Bullion or Proof coin only and is substantially more valuable than its nominal value of One Pound.
From a coin collectors perspective, a Sovereign coin, depending on the year, condition and method of minting, could be worth anything from a couple of hundred Pounds to several tens of thousand of Pounds GBP. The collector value of the Sovereign may reflect the price of gold more than the coin itself.
These coins are often used in jewellery with a value of the order of £100.