Donne's earliest poems showed a developed knowledge of English society coupled with sharp criticism of its problems. His satires dealt with common Elizabethan topics, such as corruption in the legal system, mediocre poets, and pompous courtiers. His images of sickness, vomit, manure, and plague reflected his strongly satiric view of a society populated by fools and knaves. His third satire, however, deals with the problem of true religion, a matter of great importance to Donne. He argued that it was better to examine carefully one's religious convictions than blindly to follow any established tradition, for none would be saved at the Final Judgment, by claiming "A Harry, or a Martin taught [them] this."
Donne's early career was also notable for his erotic poetry, especially his elegies, in which he employed unconventional metaphors, such as a flea biting two lovers being compared to sex. Donne did not publish these poems, although they circulated widely in manuscript form. One such, a previously unknown manuscript that is believed to be one of the largest contemporary collections of Donne's work (among that of others), was found at Melford Hall in November 2018.
Some have speculated that Donne's numerous illnesses, financial strain, and the deaths of his friends all contributed to the development of a more sombre and pious tone in his later poems. The change can be clearly seen in "An Anatomy of the World" (1611), a poem that Donne wrote in memory of Elizabeth Drury, daughter of his patron, Sir Robert Drury of Hawstead, Suffolk. This poem treats Elizabeth's demise with extreme gloominess, using it as a symbol for the Fall of Man and the destruction of the universe.
The increasing gloominess of Donne's tone may also be observed in the religious works that he began writing during the same period. Having converted to the Anglican Church, Donne quickly became noted for his sermons and religious poems. Towards the end of his life Donne wrote works that challenged death, and the fear that it inspired in many men, on the grounds of his belief that those who die are sent to Heaven to live eternally. One example of this challenge is his Holy Sonnet X, "Death Be Not Proud".
Even as he lay dying during Lent in 1631, he rose from his sickbed and delivered the Death's Duel sermon, which was later described as his own funeral sermon. Death's Duel portrays life as a steady descent to suffering and death; death becomes merely another process of life, in which the 'winding sheet' of the womb is the same as that of the grave. Hope is seen in salvation and immortality through an embrace of God, Christ and the Resurrection.