Professor Grierson, in his series of presidential addresses to the Royal Numismatic Society, spoke round the theme of methodology; and in the first of them called attention to the surprising fact that even so distinguished a scholar as L. A. Lawrence, in his definitive study of the coinage of Edward III from 1351, had miscopied, it is true by only a matter of ten days or so, ‘;a date as cardinal in English numismatics as that of the indenture between Edward III and the masters of the mint for the introduction of the groat in 1351’. It may not be inappropriate, therefore, in this presentation volume to one to whom numismatists owe so much, to review an aspect of this same study, namely privy-marking and the trial of the pyx.

‘Secret’ marks are a commonplace on later medieval coinage. In earlier times in England privy marks, seemingly part of the internal control system of the mint, are found on, for example, the York coinage of Athelstan (924–39) and, although something comparable continued into the reign of Edgar, their use broadly lapsed until the 1351 coinage of Edward III. In the France contemporary with Edward III privy marks were first put on the coins to identify their progressive debasement, and in 1389 a pellet was introduced below one of the letters on one or both sides to denote the mint at which the coins had been produced.