While the precepts of religious iconography were responding to changes in the political and religious landscape, the same was true of secular iconography, which became more complex. Expressed in a variety of motifs – mythological themes to portraits and lives; apotheosis to battles; symbolic representations and allegories to genre painting and landscapes – iconography developed into a complex language largely expressed in unity throughout all of the arts. During the Baroque period, in both religious and secular art, the iconographic theme was directly involved with the problem of allegorical representation. All artists, therefore, used specific handbooks to attend to the complex allegories that they frequently employed.