The wizard system would not seem all that strange to residents of the British Isles before the 1971 conversion to a decimal system. The old system was based on the system of weights used for precious metals, the Troy system.

A pound of silver = 12 ounces = 240 pennyweights = 5760 grains in the Troy system. The value of the British Pound Sterling was originally one Troy pound of silver. The original British penny was a small coin containing one pennyweight of silver.

For centuries all coins worth a shilling or less were minted in silver, while those above a shilling were gold. Coins weren't minted at a value of more than a pound as there were few things with values that high and the weight of the coinage would have been excessive.

While the basic denominations were Pound [£ - from the Latin liber], Shilling [s], and Penny [d - from the Latin denarius], there was a wonderfully diverse collection of coins and values in use over the years.

Old denominations:

• Farthing = ¼ penny
• Halfpenny = ½ penny [Ha'penny]
• Penny
• Tuppence = 2 pence
• Truppence = 3 pence
• Groat = 4 pence
• Sixpence = 6 pence [tanner]
• Shilling = 12 pence [bob]
• Florin = 2 shillings = 24 pence
• Half Crown = 2½ shillings = 30 pence
• Crown = ¼ pound = 5 shillings = 60 pence
• Ten Shilling Note = ½ pound = 10 shillings = 120 pence [dollar]
• Mark * = 13 shillings 4 pence = 160 pence [used in old real estate transactions]
• Pound Note = 4 crowns = 10 florins = 20 shillings = 240 pence [quid]
• Sovereign = 1 pound [gold coin]
• Guinea * = 1 pound 1 shilling = 252 pence [used to price expensive items]

* There is no actual coinage in these denominations, but they appear in court papers and advertisements.

The pre-1971 penny was huge. A bronze coin larger than an American silver dollar, you dreaded getting them in change. Fortunately there was usually a large paper-maché figurine in shops into which you could insert them as a donation to charity. The existence of the tuppence, truppence, & groat made sense when you thought about carrying five penny coins in your pocket or purse.

If you have ever seen one of the antique bicycles with the large front wheel and tiny rear wheel, and have been to Britain, you can understand why they were called "penny-farthings".