The Prose Works of Jonathan Swift, D. D., Vol. VI
Small copper coins becoming scarce, several individuals, without permission, issued tokens; but the practice was stopped. In 1680 Sir William Armstrong, son of Sir Thomas, with Colonel George Legg (afterwards Lord Dartmouth), obtained a patent for twenty-one years, granting them the right to issue copper halfpence. Coins were actually struck and circulated, but the patent itself was sold to John Knox in the very year of its issue. Knox, however, had his patent specially renewed, but his coinage was interrupted when James II. issued his debased money during the Revolution (see Monck Mason, p. 334, and the notes on this matter to the Drapier's Third Letter, in present edition).