“Can any man say with certainty that he was happy at a particular moment of time which he remembers as being delightful? Remembering it certainly makes him happy, because he realizes how happy he could have been, but at the actual moment when the alleged happiness was occurring, did he really feel happy? He was like a man owning a piece of ground in which, unknown to himself, a treasure lay buried.”

Book III, Ode 29, lines 65–68.
Imitation of Horace (1685)

Ch 10
The Little Lame Prince and his Travelling Cloak (1875)
Context: Thus King Dolor's reign passed, year after year, long and prosperous. Whether he was happy — "as happy as a king" — is a question no human being can decide. But I think he was, because he had the power of making everybody about him happy, and did it too; also because he was his godmother's godson, and could shut himself up with her whenever he liked, in that quiet little room in view of the Beautiful Mountains, which nobody else ever saw or cared to see. They were too far off, and the city lay so low. But there they were, all the time. No change ever came to them; and I think, at any day throughout his long reign, the King would sooner have lost his crown than have lost sight of the Beautiful Mountains.

Esoteric Encyclopedia of Eternal Knowledge

"Articles of Belief and Acts of Religion" (1728).
1720s

Source: Cancer Ward

Part II, Ch. I
The Possessed (1872)

Micah Sparks, Chapter 17, p. 339
2000s, Three Weeks with My Brother (2004)

Source: Ouran High School Host Club, Vol. 13