What do a bob, crown and guinea have in common?

After the Norman Conquest in 1066, the British pound was divided into 20 shillings or 240 pennies. Until decimalization in 1971, money was divided into pounds (£) shillings (s) and pennies [or pence] (d). The symbols s (for shilling) and d (for pence) derive from the Latin solidus and denarius which were the names of coins used in the Roman and Byzantine empires. The £ sign developed from the latin word libra, which refers to weighing scales. The shilling was subdivided into 12 pennies. The penny was, in turn, subdivided into two halfpennies or four farthings (quarter pennies). It was based on the troy system of weighing precious metals where the penny was literally one pennyweight (1,89 grams) of silver. A pound sterling thus weighed 240 pennyweights, or a pound (453 grams) of sterling silver. There were also commonly used terms to describe particular denominations, for example: Two farthings were one halfpenny (or hay-pence). Two halfpence was one penny 3 pence was called thruppence...