This word was originally feorthing, and the term "fourthing" occurs in the Anglo-Saxon version of the Gospels (Matthew v. 26, and Luke xxi. 2).
At first the Farthing was the fourth part of a silver penny, and it no doubt received its name from the practice of cutting pennies into quarters; specimens of these have been found dating back to the time of Edward the Confessor.
Farthings of silver were first struck under Edward I for England, although John had coined them as Lord of Ireland in 1210. Gold farthings are mentioned in an Act of the ninth year of Henry V, i.e., 1421; and a project for coining farthings in tin was brought up about 1679, and this metal was used for them to a small extent in the latter part of the reign of Charles II.
James I, in 1613, granted a patent to Lord Harington, of Exton, in the county of Rutland, to strike Royal Tokens, each of the nominal value of one farthing. These pieces were nicknamed Haringtons.
The silver farthings were last coined in the reign of Edward VI, and in 1561 a three-farthing piece was ordered to be struck. This was discontinued in 1582.
The copper farthing was originally struck in the reign of James I. In 1635, a farthing token, called the Rose Farthing, or Royal Farthing, was issued; it was coined in copper, but was sometimes composed of two metals to make counterfeiting more difficult. It obtained its nmae from the rose surmounted by a crown on the reverse.
The proclamation of Charles II, dated August 16, 1672, amde the farthing a legal tender only for sums less than sixpence. In the reign of James II the farthings were made of tin, with a square plug of copper in the centre.
During the reign of Queen Anne no copper money was struck for currency, but patterns for farthings were minted. One of these, executed shortly before the Queen's death, gave rise to the vulgar error that only three farthings were issued in this reign. This variety was put in circulation and is not rare.
Half Farthings were struck in 1828 and later, for use in Ceylon; one third Farthings appeared in 1827 to supersede the Grani of Malta; quarter Farthings have also been issued for colonial use.
Source: Frey's Dictionary (American Journal of Numismatics, Vol. 50, 1916)