In the last decade of his life, Claude Lorrain concentrated on a limited number of themes, many of them from Virgil's Aeneid. The Apollo and the Muses on Mount Helion (Parnassus) of 1680 in the Boston Museum of Fine Arts is a good example of his use of idyllic mythology during his last years. His technique remained as refined as in his earlier years, but his compositions often lost the earlier sense of perfect balance in the trees of different sizes and densities on each side of the picture. Sometimes, as in the Boston picture, the whole appears rather awkward, especially in reproductions which tend to emphasize the patterns made by the landscape against the sky. In front of the original, however, these awkwardnesses disappear because one becomes aware that the artist is concentrating entirely on atmosphere, to the exclusion of everything else.
      The mythological story depicted in the Apollo and the Muses on Mount Helion by Lorrain is the following.
      Apollo, as the God of Poetry and Music (in this role named Apollo Musagetes), dwells on Mount Parnassus, accompanied by the muses, the goddesses of poetic inspiration and the creative arts in general. The running brook is the Castilian spring, which, like another, the Pierian, was a source of inspiration and learning where we are advised to drink deep.