As do his plays, Shakespeare’s sonnets introduce themes reflecting Renaissance thought. In order to understand them, one must realize what the term “Renaissance” implies. The word was introduced into art criticism by John Ruskin in The Stones of Venice (1851-1853), when he referred to a return to “pagan systems” in Italian painting and architecture during the fourteenth century. Essayist Walter Pater extended the meaning of the term to include all phases of intellectual life. Scholars have associated with the Renaissance such phenomena as Neoplatonism, humanism, and classicism. Recently, they have also deduced that medieval traditions were not utterly displaced; there was no sharp dividing line.

Perhaps the most obvious theme in Sonnet 73 is that of mutability, deriving from Greek and Roman philosophers, but strained through the theological thinkers of the Middle Ages and modified during the Renaissance. Basically, it describes all “sublunary” phenomena (those beneath the moon, thus corrupted) as subject to change. Thus they lack the permanence both of biblical perfection and of Platonic ideals.

In this sonnet, Shakespeare’s consciousness of himself and of his beloved friend remains rooted in mortality and mutability. Unlike the idealized relationship portrayed in earlier sonnets, here there is a strong consciousness of the changes that old age brings to the poet and to his relationships with others. Here is resignation in the face of the inevitability of death and his permanent separation from his beloved. Time becomes omnipotent. It controls all natural processes, and no expedient of art can resist it. The most one can do is to express a heightened affection for one who is soon to pass away.

If one examines the consistency with which Shakespeare has joined his three sets of images, one may glimpse something of the coherence created by the poet’s genius. The words “bare ruined choirs” of the first quatrain are strengthened in the second into the words “Death’s second self.” In the third, what was previously merely a metaphor for sleep has become metaphorically a deathbed. The concluding couplet may be considered a further step still, since it translates metaphorical references to death into personal ones referring to the poet’s own approaching end.

It has been shown that the poet uses a variety of colors within the quatrains of this sonnet: yellow, black, and red (glowing). These colors have suggested to other poets images of death and pestilence. Shakespeare uses them to describe metaphorically his approaching old age. Thus he maintains the theme of inevitable change and sublunary corruption throughout.