John Donne's poetry is full of extravagant conceits. Although this poem, "Death Be Not Proud," is addressed to Death personified, it is really counseling the reader not to fear death because it is not really a "mighty and terrible" thing but something that is common and contemptible. Donne seems to have been strongly influenced by some of Shakespeare's sonnets on the subject of death, especially Sonnet XIX which begins:
Devouring Time, blunt thou the lion's paws,
And make the earth devour her own sweet brood,
Pluck the keen teeth from the fierce tiger's jaws,
And burn the long-liv'd phoenix in her blood . . .
Shakespeare is addresssing Time as Donne is addressing Death. A few lines later in Shakespeare's sonnet he audaciously says:
But I forbid thee one most heinous crime . . .
He actually forbids Time to damage his loved one's looks. This type of poetic conceit appealed to Donne, who carried it even further.
See also Shakespeare's beautiful Sonnet LV, which begins:
Not marble, nor the gilded monuments
Of princes, shall outlive this powerful rhyme;
But you shall shine more bright in these contents
Than unswept stone, besmear'd with sluttish time.