1898, James Harvey Robinson, Henry Winchester Rolfe, Petrarch, the First Modern Scholar and Man of Letters, New York: G.P. Putnam's Sons, published 1909, page 229:
This may be accounted for largely on the ground that Cicero and Petrarch were men of the same temperament and cast of mind. They were both typical men of letters. The man of letters is intellectually alert; sensitive to impressions and able to report them; hospitable to all ideas of his time; […]