William Shakespeare composed "Sonnet 19" in the 1590s, publishing it in 1609 as part of what's now known as the "Fair Youth" sonnet sequence. Like others in this sequence, the poem meditates on the fleeting nature of youth and beauty. The speaker personifies time as a "devouring" force and suggests that even the strongest, most powerful creatures in the world are susceptible to decay and change. For this reason, the speaker asks time to leave the speaker's lover alone, hoping to protect the lover's youthful beauty. By the end of the poem, though, the speaker insists that it doesn't matter whether time ruins the lover's beauty, since the poem itself will preserve this beauty forever.