This section is from "The American Cyclopaedia", by George Ripley And Charles A. Dana. Also available from Amazon: The New American Cyclopędia. 16 volumes complete..
Penny, an English coin and money of account, equal to 1/2 of a shilling. It was the only coin generally current among the Anglo-Saxons, and the most ancient except the sceat-ta. The name seems to be the same as the German Pfennig, and connected with the old German pfant, a pledge, and the Latin pendere, to weigh out, hence to pay. It was made of silver, and weighed 22 1/2 grains troy, or 1/240 of the Saxon pound, corresponding to the Roman denarius,1/240 of the libra. The ancient penny was divided by a deeply indented cross into four quarters, which might be broken apart; whence the terms halfpenny and farthing, which were not coined separately until the time of Edward I. In the reign of Edward III. its weight was reduced to 18 grains, in that of Edward IV. to 12, in that of Edward VI. to 8, and in that of Queen Elizabeth to 7 23/31or 1/62 of an ounce in silver, which value was retained till 1860. Copper halfpence and farthings were first coined in 1672, but the copper penny was not introduced till 1797; twopenny pieces were coined at the same time, but soon withdrawn because too large for circulation. In 1860 a new bronze coin was introduced to replace the old copper coinage.
The bronze penny is of only about half the value of the old copper penny.
 
Continue to: