La Salle Debain

It seems I have been wrong about the origins of the Seville Orange joke

Rather than Algernon Sidney It would appear to have been quipped by an 18th century Anglo-Irish actor named James Quin as recounted in "Lives of the Players" by John Galt (not that John Galt but this one) in 1831.

Quin once, in the character of Cato, received a blow in his face by an orange thrown from the upper gallery; such a circumstance would have disconcerted many an actor possessed of less presence of mind, but instead of being disturbed, he wiped his face, and taking it up, observed, "It was not a Seville orange."

A proto-version of the joke does date back to Sidney's time. It was made by none less than William Shakespeare in "Much Ado About Nothing" Act II, Scene 1:

DON PEDRO: Why, how now, count! wherefore are you sad?

CLAUDIO: Not sad, my lord.

DON PEDRO: How then? Sick?

CLAUDIO: Neither, my lord.

BEATRICE: The count is neither sad, nor sick, nor merry, nor well; but civil count, civil as an orange, and something of that jealous complexion.

Note Don Pedro is from Aragon which is close enough to Seville for Elizabethan comedy purposes.

But while 300+ years is impressive, this joke from Sumeria c. 19th-16th centuries BC is older by far:

Something which has never occurred since time immemorial: a young woman did not fart in her husband's lap.

See The world's ten oldest jokes