“Courteous love was avowedly a form of drama, but not the less a force of society. Illusion for illusion, courteous love in Thibaut's hands, or in the hands of Dante and Petrarch, was as substantial as any other convention;— the balance of trade, the rights of man, the Athanasian Creed. In that sense the illusions alone were real; if the middle-ages had reflected only what was practical, nothing would have survived for us.”

Fiction, Time for a Tiger (1956)

"Queen of the Black Coast" (1934)
Source: Conan the Barbarian Omnibus -The Original Stories
Context: He shrugged his shoulders. "I have known many gods. He who denies them is as blind as he who trusts them too deeply. I seek not beyond death. It may be the blackness averred by the Nemedian skeptics, or Crom's realm of ice and cloud, or the snowy plains and vaulted halls of the Nordheimer's Valhalla. I know not, nor do I care. Let me live deep while I live; let me know the rich juices of red meat and stinging wine on my palate, the hot embrace of white arms, the mad exultation of battle when the blue blades flame and crimson, and I am content. Let teachers and priests and philosophers brood over questions of reality and illusion. I know this: if life is illusion, then I am no less an illusion, and being thus, the illusion is real to me. I live, I burn with life, I love, I slay, and am content."

are none the less valuable for being quoted.
The Gander, in Book Seven : What Saraïde Wanted, Ch. XLV : The Gander Also Generalizes
The Silver Stallion (1926)

"The Present Outcome of Psychoanalysis", p. 189
The Denial of Death (1973)

The Gander, in Book Seven : What Saraïde Wanted, Ch. XLV : The Gander Also Generalizes
The Silver Stallion (1926)
Context: Nothing … nothing in the universe, is of any importance, or is authentic to any serious sense, except the illusions of romance. For man alone of animals plays the ape to his dreams. These axioms — poor, deaf and blinded spendthrift! — are none the less valuable for being quoted.

Source: 2010s, Waking Up (2014), p. 82

Acis, in Pt. V
1920s, Back to Methuselah (1921)

Variant: Infinite love is the only truth. Everything else is illusion.
Source: Davidicke.com