According to Colin Wilson’s book on Existentialism published in 1983, the 12^th c. Iranian mathematician and philosopher “Omar Khayyam is in a far sounder position than Sartre as an existential thinker.  Sartre says we know nothing except that men need bread and justice.  Omar Khayyam replies that we know nothing except that politicians and philosophers die like animals, so we had better ‘fill the cup’ and enjoy the present.”

[pic source @ Harry Ransom Center-The Univ of Texas:  “Souvenir menu for the annual dinner of The Omar Khayyam Club of America, 1919”… for educational purposes only]