Final answer:
Sir Walter Raleigh, an adventurer and courtier of Queen Elizabeth I, was the friend and contemporary of poet John Donne, and is remembered for his efforts to colonize the New World.
Step-by-step explanation:
The explorer and friend of the poet John Donne you are referring to is Sir Walter Raleigh. He was indeed an adventurer, a favorite courtier of Queen Elizabeth I, a devout Protestant, and a privateer against Spanish fleets.
As an individual of significant influence during the Elizabethan age, Sir Walter Raleigh is best remembered for his attempts to colonize the New World, including his efforts to establish the Roanoke Colony.
In the realm of literature and poetry, however, he was connected to Donne and other poets of the time who were deeply engaged in the cultural and intellectual discourse of their era.