“I have designed a decorative and monumental work as a group of subjects representing the three ages of sacred and profane mythology: the Golden Age, the Silver Age and the Iron Age. I have symbolised these different ages by dividing each one into compositions representing the three phases of the day: morning, noon and evening.
The Golden Age comprises three compositions (Adam and childhood):
:1. Prayer at sunrise.
:2. A walk in Paradise or the ecstasy before nature.
:3. All nature asleep.
The Silver Age. The second phase is taken from pagan mythology (Orpheus and youth):
:1. The dream nature is revealed to the senses of the inspired poet.
:2. The song.
: 3. Orpheus in the forest, his lyre broken and he longs for unknown countries and immortality.
The Iron Age (Cain and the maturity of man):
:1. The Sower making the earth productive (production).
:2. The Ploughman (work).
:3. Death (Cain and Abel).
Fourth panel:
The Triumph of Christ.
These three periods of humanity also correspond to the three periods in the life of a man:
The purity of childhood: Adam –
The poetic and unhappy aspirations of youth: Orpheus –
The grievous sufferings and death of mature age: Cain with the redemption of Christ.
D— thought it was an extremely ingenious and intelligent device to have used a figure from pagan antiquity for the cycle of youth and poetry instead of a Biblical figure, because intelligence and poetry are far better personified in these periods which were devoted to art and the imagination than in the Bible which is all sentiment and religiosity.
The Golden Age: the beginning of the world, naïveté, candour, purity. The morning: prayer. Noon: ecstasy and evening: sleep. No passion, nothing but elementary feelings. —
The Silver Age, corresponding to the civilization of humanity, already begins to feel emotion; it is the age of poets. I can only find this cycle in Greece. The morning: inspiration. Noon: song. Evening: tears. —
The Iron Age. Decadence and fall of humanity. I shall represent Cain ploughing and Abel sowing. Noon: Cain rests while Abel tends the altar of the Lord from which smoke, a symbol of purity, rises straight to the heavens. The evening: death at the hands of Cain.
The first death corresponds to the other deaths in the two other paintings: sleep and death of the senses; tears and the death of the heart. Do you understand the progression?
Sleep, though sad, is gentler than tears which, though painful, are gentler than death. Ecstasy is more delightful than song, which is gentler than work. Prayer is superior to dreaming which is more elevated than manual work.”

Notes to his mother, on The Life of Humanity (1884-6) http://www.wikiart.org/en/gustave-moreau/humanity-the-golden-age-depicting-three-scenes-from-the-lives-of-adam-and-eve-the-silver-age-1886, his composition of a ten image polyptych, p. 48 ·  Photo of its exhibition on the 3rd Floor of Musée National Gustave Moreau http://en.musee-moreau.fr/house-museum/studios/third-floor
Gustave Moreau (1972)