In 1943, when the Art Institute acquired Inventions of the Monsters, Salvador Dalí wrote his congratulations and explained:
According to Nostradamus the apparition of monsters presages the outbreak of war. The canvas was painted in the Semmering mountains near Vienna a few months before the Anschluss [the 1938 political union of Austria and Germany] and has a prophetic character. Horse women equal maternal river monsters. Flaming giraffe equals masculine apocalyptic monster. Cat angel equals divine heterosexual monster. Hourglass equals metaphysical monster. Gala and Dalí equal sentimental monster. The little blue dog is not a true monster.