5. Newton’s eighteen-month breakdown was recognized by contemporaries
One of the only two close personal relationships developed by Newton during his lifetime was with Nicholas Fatio de Duillier, a protégé with whom he maintained a warm correspondence. The relationship led to speculation among some that since Newton never married he was involved in a homosexual relationship with Fatio. There has never been any evidence of such a relationship revealed in Newton’s voluminous works and correspondence, and there is much evidence that Newton had no interest in either sex, preferring to remain chaste and free from emotional encumbrances. He often wrote complaining of others who attempted to present him to eligible women.
During the period of his breakdown, during which he suffered from tremors, insomnia (in one letter he claimed to have not slept for five days), an inability to eat, delusions and possibly hallucinations, he also sent letters which appeared to his correspondents to be irrational in nature. One of these was to Fatio, and the former regard in which his protégé had held him vanished. Newton claimed in a letter to Samuel Pepys to have lost “my former consistency of mind” and he was struck by apathy and what was referred to by others as melancholia. His evident illness included him being reported to have conversations with persons not present, seemingly responding to voices heard in empty rooms.