It's almost always a safe bet that a Donne poem will be about a woman, God, or death—or some combination. So, even though this is a love poem, it's not too surprising that we start off with a metaphor about an old man dying. In this poem, though, Donne gives death dignity—it's a peaceful and welcome thing. It's also his first connection to love. Even though their parting will feel a little like a death, their love is so pure, powerful, and good that they can endure it gently, without any outward sorrow.