The painting depicts three human heads, an old man, a mature man and a young man, towering over three animal heads, respectively, a wolf, a lion and a dog.
Above the portrait Titian has added a slogan that explains the meaning of the allegory: “Based on the past / present acts prudently / not to spoil the future action.” ( “Sulla base del passato / il presente prudentemente agisce / per non guastare l’azione futura.”)
Under the human heads there are the heads of three animals: the wolf feeds on memories of the past; the lion is the force with which it is necessary to conduct the present; while the dog, able to flatter, seems to look to the future with insouciance.
Titian’s visual formulation of this theme is so unique that it had not direct predecessors or followers. Literary and artistic traditions of animal iconography combined with exegetic methods applied in religious and mythological allegory were utilized by Titian to reinforce veiled levels of meaning in imagery. Two tricephalous images: three human: past experience, present perspicuity and future foresight. Three animal heads: a wolf, a lion and a dog. These have been identified with Alexandrian God Serapis, popular in Renaissance egyptianizing and pseudo-hieroglyphic literature. Macrobius in the Saturnalia established a parallel moral and a temporal significance which tied the anthropomorphic and theriomorphic triads. Erwin Panofsky wrote an ingenious and intellectually dazzling analysis of the Allegory of Prudence. In his final remarks he conceded that the “ abstruse allegory which is also a moving human document would never have been judged worthy of our attention if we had not first been captivated by the beauty of its form”. In a work of art form cannot be divorced from content. Titian delights us with the visual spectacle and with a more-than-visual-meaning engaging us in the process of interpretation.
Erwin Panofsky, University of Chicago Press, 1955 https://books.google.it/books/about/Meaning_in_the_Visual_Arts.html?id=6CYtZjucAhcC&redir_esc=y