Philip Sidney, "Jane the Quene," Being Some Account of the Life and Literary Remains of Lady Jane Dudley, Commonly Called Lady Jane Grey (London: S. Sonnenschein, 1900), p. 90

I have here sent you, my dear sister Catherine, a book, which although it be not outwardly trimmed with gold, or the curious embroidery of the artfullest needles, yet inwardly it is more worth than all the precious mines…