The silver penny was introduced to England around the year 785 by King Offa of Mercia, in the English midlands. The currency was decimalised in 1971 which meant the discontinuation of the penny at that time. A new penny was minted that was worth 2.4 times the value of the old coin.
The name penny comes from the Old English pennige (roughly pronounced 'penny-yeah', IPA [penije]). It shares its roots with the German pfennig, which was a German denomination. The coins were similar in size and weight to the continental deniers of the period. The abbreviation d. comes from the Roman denomination denarius and was used until the 1970s.
Anglo-Saxon silver pennies were the currency used to pay the Danegeld, essentially protection money paid to the Vikings so that they would go away and not ravage the land: as an illustration of how heavy a burden the Danegeld was, more Anglo-Saxon pennies of the decades around the first Millennium have been found in Denmark than in England. In the reign of Ethelred the Unready (978-1016), some 40 million pennies were paid to the Danes, while King Canute (Knut) (1016-1035) paid off his invasion army with another 20 million pennies. It is estimated that the total amount of silver paid in Danegeld between 990 and 1015 was about 93 tons of silver, worth about £250,000 at the time, and equivalent to about £1.2 billion in today's money.
The penny initially contained 1/240th of a Troy pound (approx. 373 grams) of silver, i.e. about 1.55 grams. As the purity and weight of the coin was critical, the name of the moneyer who manufactured the coin, and at which mint, often appeared on the reverse side of the coin.
From the time of King Offa, the penny was the only denomination of coin minted in England for some five hundred years, until the attempted gold coinage issue of King Henry III, and the later issues of King Edward III.
See also: British coinage