Contrary to the rest of the characters of The Scarlet Letter, John Winthrop is a real historical figure. Born in England in 1588, Winthrop was a puritan, and a part of the British gentry during the rule of Charles I. Issues within the kingdom threatened him with the possibility of seeing his estates diminished. For this reason, he joined the Massachusetts Bay Company as a leading investor. The purpose of this company was to get a royal charter to create a colony in New England. Seeing the chance to escape what was becoming a shaky monarchy, Winthrop sold his property and came to America with his family. He was then elected as the first governor of the Massachusetts Bay colony.
Aside from being the people's leader, Winthrop was also an idealist whose political philosophies were based on theocracy, or the ruling according to the teachings of the Bible. A fervent puritan, Winthrop ultimately aimed to turn the colony of Massachusetts into a form of religious utopia. It is said that, for the twelve years that he was governor of Massachusetts, the colony did prosper. However, he has also been described as intolerant, radical, and extremist when it comes to his religious fervor.
The addition of Winthrop as a character in The Scarlet Letter serves several purposes. First, his death in the novel represents the death of the old rule and the beginning of a new reality for the settlers. Notice how Winthrop's death is placed quite close to Dimmesdale's admission of guilt. This juxtaposition is ironic because Dimmesdale's confession will basically expose the settlement for what it really is: not the puritanical haven dreamed by Winthrop, but a place where sin and temptation are just as rampant as anywhere else. Once the saintly Winthrop dies, what will be the moral destiny of the colony? Who could be the next leader that will follow the path of John Winthrop? Surely, not Dimmesdale. Hence, the death of Winthrop adds to the atmosphere of sadness, nostalgia, and the loss of grace that is embodied by Dimmesdale in his demeanor, his bad health, and his odd behavior.
The fact that it is Hester who takes care of Winthrop in his deathbed also allows the reader to view Hester's character from another dimension: she is truly caring, and truly nurturing even though she is still bound to carry her scarlet letter, even in the presence of Winthrop.
In a final note, Winthrop's addition to the novel also adds great realism to it. This is because his role in the story is historically accurate. It is placed around the time when he would have been governor and the social situation within the settlement was probably quite accurately described by Hawthorne as well.