Donne was a cleric (priest) in the Church of England and rose through the hierarchy to become the Dean of London's St. Paul's Cathedral. He is known for sleeping in a coffin to remind himself of his own mortality. He is also famous for using the fast-moving sands in an hour glass he would turn over while preaching to illustrate the speed with which human life passes.
Donne was often called metaphysical: this describes the school of poetry for which he is the most famous example but also describes his belief that life continues on after death. He illustrates this idea in many of his poems, such as in the defiant "Death Be Not Proud," in which he states:
One short sleep past, we wake eternally,
And Death shall be no more; Death, thou shalt die.
In his love poetry, Donne both celebrated physical, carnal love and expressed the metaphysical idea that true love has a strong spiritual component that ties lovers together: even if they are physically far apart, lovers are still one. In "A Valediction: Forbidding Mourning," he writes:
Our two souls therefore, which are one,
Though I must go, endure not yet
A breach, but an expansion,
Like gold to aery thinness beat.
In his poetry, Donne also scorned love that was only based on physicality, seeing this as superficial: true love requires a spiritual connectedness between the lovers.
Donne's poetry moves away from cliches about faith or stock images to affront us and make us think. He uses unusual metaphors that startle us and yet point to the reality of the divine, illustrating the way that, to him, the spiritual space (that can seem out of the reach of our senses) is a continuation of who we are.