For an avowed atheist, who viewed life as a tragic absurdity between two voids, the death of a lover opened as deep and complex a well of feeling as the death of Christ opens in a believer; the whole nature of existence is brought into question. As if impelled by the force of his emotions, Bacon the atheist had ransacked the central rituals of both the Greek and Christian faith: only there, he was convinced, could he find a structure to convey the extent and the implication of his own drama.

That drama – of art demanding the sacrifice of the artist – lies at the heart of the whole enigma of Bacon’s art.

Peppiatt, Francis Bacon: Anatomy of an Enigma