God is dead
This quotation is widely attributed to Friedrich Nietzsche (1844-1900), who wrote in Die Frohliche Wissenschaft, 1882:
"God is dead: but considering the state the species Man is in, there will perhaps be caves, for ages yet, in which his shadow will be shown."
Nietzsche had some help in forming that thought. In 1854, Gérard de Nerval (the nom-de-plume of the French poet and translator Gérard Labrunie), wrote, in his Le Chiméres:
"Dieu est mort! le ciel est vide - Pleurez! enfants, vous n'avez plus de pére" (God is dead! Heaven is empty - Weep, children, you no longer have a father)
This earlier version of God is dead was itself a summary of Jean Paul's Blumen-Frucht-und-Dormstucke, 1976 - in which God's children are referred to as 'orphans'.
In The Republic, Plato wrote:
"Behold! human beings living in underground den ... like ourselves ... they see only their own shadows, or the shadows of one another, which the fire throws on the opposite wall of the cave."
Nietzsche's version appears to have been assembled from the pieces by de Nerval and Plato.