I lie here alone and in silence, enveloped in the manifold black wrappings of darkness, tedium, unfreedom, and winter - and yet my heart beats with an immeasurable and incomprehensible inner joy, just as if I were moving in the brilliant sunshine across a flowery mead. And in the darkness I smile at life, as if I were the possessor of charm which would enable me to transform all that is evil and tragical into serenity and happiness. But when I search my mind for the cause of this joy, I find there is no cause, and can only laugh at myself. I believe that the key to the riddle is simply life itself; this deep darkness of night is soft and beautiful as velvet, if only one looks at it in the right way.
— Rosa Luxemburg, letter from prison, Mid-December, 1917