Mann's The Holy Sinner is an epic of arch-sinfulness - witting and unwitting - of retribution and penance, and in the finish of triumphant humility.

Duke Grimald of Flanders had twin children - a boy and a girl of unsurpassed loveliness. From their incestuous union sprang Grigorss...and the child was exposed in a brak at sea. Rescued, the boy was reared in holiness in the Channel Islands, but later returned by chance and, after defending his mother from her enemies, who were threatening the dukedom to which she has succeeded on her brother's death, like Oedipus married her. Seventeen years of solitary penance followed the discovery of this crime against nature, and then simultaneous dream-visions proclaimed to two pious leading citizens of Rome that Gregorius was to be the next tenant of the papal throne.

This saga of stark horror and pity may claim to rank among Mann's greatest works.