Although Adams and Dickinson had worked closely together in the First Continental Congress, the latter's moderation and insistence upon taking every step toward reconciliation alienated Adams and others who supported vigorous measures of opposition to Great Britain. An open breach between the two men was caused by Adams' reference to Dickinson (although unnamed) as a “piddling Genius” in his letter to James Warren of 24 July 1775 (below), which was intercepted by the British.

In 1779 Du Simitière sent from Philadelphia to France a set of fifteen profile drawings done from life, which he wanted engraved to sell as a set. Fourteen of the drawings were of Americans whom Du Simitière considered “eminent”; the fifteenth was of Conrad Alexandre Gérard, who carried the drawings with him on his return and was to arrange for their engraving. Apparently only fourteen engravings were made, each likeness being numbered. Dickinson's was No. 11. Some of the engraved sets were captured by the British on their way to America and were pirated by two British publishers, William Richardson and R. Wilkinson. These unauthorized engravings are readily identifiable, for the publishers did not hesitate to have their names inscribed (Edna Donnell, “Portraits of Eminent Americans after Drawings by Du Simitière,” Antiques, 24:17–21 [July 1933]). For Du Simitière see DAB .