If only I'd chosen an easy work! But, precisely, I, who am sterile and crepuscular, have chosen a terrifying subject, whose sensations, if they are strong, reach the point of atrocity, and if they are vague, have the strange attitude of mystery. And my Verse hurts me at times, and wounds me as if it were of iron! I have, moreover, found an intimate and unique way of painting and noting down the very fleeting impressions. I should add, which is even more terrifying, that all these impressions follow one another as in a symphony, and I often have entire days when I ask myself if this impression can accompany that one, what is their relationship and effect … You can guess that I write few lines in a week.

On his unfinished work Hérodiade, in a letter to Henri Cazalis (15 January 1865)