Calvert was so influenced by William Blake's wood engravings that <em>The Sheep of His Pasture</em> is directly based on an illustration for <em>The Pastorals of Virgil</em>. Calvert, however, even more than Blake, exploited the ability of wood engraving to achieve the most delicate detail, so astonishing in these miniatures. Calvert's subject matter originated from a vision of the golden age of pastoral innocence and abundance that has both Christian and classical overtones. The women in <em>The Brook</em> resemble figures carved on antique gems, and the tree stumps symbolize the transitory nature of life.