Guillaume Henry of Guernsey (circa 1720-1767) is considered to have been the finest of the Channel Islands silversmiths, and he was favourably compared to London makers of the day. Museums holding his work include a christening cup at the Victoria and Albert Museum and another at Dublin Museum. His harp mark has periodically been confused with the Dublin town mark.
The Transactions of the Guernsey Society records his demise thus: 'Guillaume Henry, excellent and clever goldsmith and engraver, who raised himself by his own efforts, almost without help from any master, to the highest rank of thse two noble professions, was buried the 10th of February 1767.' (R. H. Mayne, Old Channel Islands Silver, 1969, pp. 64-65). Plates 27-29 in Mayne illustrate further articles and marks by Henry, plate 28 showing marks on a baluster jug which are almost identical to those on the present tankard.