Overview
The two guinea piece was a gold coin first minted in England in 1664 with a face value of forty shillings. The source of the gold used, also provided the coin its name - the "guinea", with the regular addition of an elephant or castle symbol on the earliest issues to denote bullion supplied by the Royal African Company. For most of its period of production, the coin weighed between 16.7 and 16.8 grams and was 31-32 millimetres in diameter, although the earliest coins of Charles II were about 0.1 grams lighter and 1 millimetre smaller.
The Two guinea coin was produced in 1664, 1665 (possibly only 1 coin), 1669, 1673, and 1675-1684 inclusive; until 1669 the weight limits were 16.6-16.8 grams, afterward 16.5-16.7 grams. The obverse and reverse of this coin were designed by John Roettiers. The obverse showed a fine right-facing bust of the king wearing a laurel wreath, surrounded by the legend CAROLVS II DEI GRATIA, while the reverse showed four crowned cruciform shields bearing the arms of England, Scotland, France, and Ireland, between which were four sceptres, and in the centre were four interlinked "C"s, surrounded by the inscription MAG BR FRA ET HIB REX [date]. The coin was considered too thin to have an edge inscription like the larger contemporary Five Guineas coin, but still required a milled edge to deter counterfeiters from simply gilding contemporary silver Halfcrown coins as well as clipping or filing down of the coin's weight. Until 1668, the milling was perpendicular to the coin, visibly providing vertical grooving, however from 1669 onwards, the milling was obliquely grained.
John Roettiers continued to engrave the dies for this denomination into the reign of King James II. In this reign, the coins weighed 16.7 grams, and were only minted in 1687 and 1688. By the early part of this reign the value of the guinea had increased to nearly thirty shillings. The kings' head faces left in this reign, and is surrounded by the inscription IACOBUS II DEI GRATIA, while the obverse is the same as in Charles II's reign except for omitting the interlinked "C"s in the centre of the coin. The edge of the coins are milled diagonally.
With the removal of James II in the Glorious Revolution of 1688, his daughter Mary, and her husband Prince William of Orange ruled jointly by agreement as co-monarchs. Their heads appear conjoined on the two guinea piece in Roman style, with William's head uppermost, with the legend GVLIELMVS ET MARIA DEI GRATIA.
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