A humorous variant of the proverb one man’s meat is another man’s poison, the phrase one man’s Mede is another man’s Persian refers to the law of the Medes and Persians, denoting something which cannot be altered.

The phrase one man’s Mede is another man’s Persian occurs, for example, in the following horoscope by Georgia Nicols, published in the Calgary Herald (Calgary, Alberta, Canada) of Sunday 6^th January 2008:

INTO EACH LIFE SOME RAIN MUST FALL

You’re focused on finances this year and next. In particular, everything related to taxes, debt and shared possessions will demand your attention. Some people pay bills when due, some when overdue, and some never do. You might get along with less because a partner has quit work. You might find your values don’t agree with somebody else’s. Oh well, one man’s Mede is another man’s Persian.

—Cf. also the humorous variants one man’s meat is another man’s poisson and one man’s mead is another man’s poison.

The earliest occurrences of the phrase one man’s Mede is another man’s Persian that I have found are as follows, in chronological order:

1-: From Judge (New York City, New York, USA) of Saturday 30^th November 1929:

According to the press, an English archaeologist has finally translated the ancient law of the Medes and the Persians. We figured it out long ago: “One Man’s Mede is Another Man’s Persian.”

2-: From a correspondence from Hollywood, California, dated Tuesday 10^th December 1929, by Mollie Merrick, published in The Detroit News (Detroit, Michigan, USA) of Tuesday 10^th December 1929:

And Jimmie Gleason’s ¹ latest: “One man’s Mede is another man’s Persian.”

¹ James Austin Gleason (1882-1959) was a U.S. actor, playwright and screenwriter.

3-: From the column With & Without Prejudice, by Thomas Jay, published in the Sunday Dispatch (London, England) of Sunday 22^nd June 1930:

An archæologist claims to have translated the ancient law of the Medes and the Persians. But years ago we were repeatedly told that one man’s Mede was another man’s Persian.

4-: From the column Advice Gratis, published in The Gippsland Times (Sale, Victoria, Australia) of Thursday 9^th October 1930:

Solemn Personage (laying down the law): “And that, mark you, is as irrevocable as the laws of the Medes and Persians.”
Fatuous Individual: “Ah, but, remember, one man’s Mede is another man’s Persian.”

5-: From All In a Lifetime: A Study In Bats, by ‘C. R. R.’, published in the Ithaca Journal-News (Ithaca, New York, USA) of Wednesday 15^th July 1931:

Well, you know the old law of the ancients: “What’s one man’s Mede is another man’s Persian.”

6-: From the column Behind the Mike, published in The Sunday Oregonian (Portland, Oregon, USA) of Sunday 10^th April 1932:

“As inflexible as the laws of the Medes and Persians,” quoth Harry Failing at lunch. “Yes,” mashugaed ² Grannatt. “One man’s mede is another man’s persian.”

² This is a verb use of mashuga, variant of meshuga, an adjective referring to foolishness or irrationality.

7-: From the column A Book a Day, by Joseph Henry Jackson, published in the San Francisco Chronicle (San Francisco, California, USA) of Saturday 30^th July 1932:

A summer week-end is a time for light reading; that much almost goes without saying.
But the difficulty is that different people have different conceptions of what light summer reading is and isn’t. And they should, for that matter. There is no fixed law about such things. They’re another example (speaking of laws) of someone’s brilliant corruption of the old saw: “What’s one man’s Mede is another man’s Persian.”

8-: From the Virginian-Pilot and the Norfolk Landmark (Norfolk, Virginia, USA) of Tuesday 20^th September 1932:

Speaking of the Maine election, the treasured Times quotes “Thy kingdom is divided and given over to the Medes and the Persians.” Still, as Mr. George S. Kaufman ³ once said, one man’s Mede is another man’s Persian.

³ George Simon Kaufman (1889-1961) was a U.S. playwright, theatre director and producer, critic and humorist.

9-: From the column Mainly About Manhattan, by John Chapman, published in the Sunday News (New York City, New York, USA) of Sunday 28^th February 1937:

George S. Kaufman once said one man’s Mede is another man’s Persian.

10-: From the column Gossip of the Theater, by Louis Sheaffer, published in the Times Union (Brooklyn, New York, USA) of Sunday 7^th March 1937:

George S. Kaufman would have you know: “One man’s mede is another man’s persian.”

11-: From the column It Seems to Me, by Heywood Broun, published in the Reading Times (Reading, Pennsylvania, USA) of Friday 14^th May 1937:

Drawing the Blue Line

I have said that it is extremely difficult to take the position that anything at all should be allowed to go, but, on the other hand, it is not easy to be logical in saying, “This should be stopped and this should be tolerated.” As George S. Kaufman remarked, “One man’s Mede is another man’s Persian.”

12-: From the column Personally Speaking, by Alan Barth, published in The Sunday Enterprise (Beaumont, Texas, USA) of Sunday 23^rd May 1937:

Our definitions of decency and morality not only change, but also at any given time are merely relative. As George Kaufman once remarked, “One man’s Mede is another man’s Persian.” There can never be any sound censorship except by the favor or disfavor of the public itself.

13-: From the column Mainly About Manhattan, by John Chapman, published in the Sunday News (New York City, New York, USA) of Sunday 18^th July 1937—the following are one of the questions submitted to John Chapman by George Lottman, a press agent, and John Chapman’s answer:

What is your favorite epigram? George Kaufman’s “One man’s Mede is another man’s Persian.”

14-: From the column Broadway, by Dan Walker, published in the Daily News (New York City, New York, USA) of Friday 31^st December 1937:

Who is to say what is the best, the biggest, the loftiest or the lowest, the wittiest or the worst, the loveliest or the lousiest among the thousands of events which crowd a year? As George Kaufman puts it, one man’s Mede is another man’s Persian, and it is differences of opinion which keep the wheels revolving and make life worth living in this passing sublunary world.

15 & 16-: From Philosopher of Folly’s Column, by Ted Robinson, published in the Cleveland Plain Dealer (Cleveland, Ohio, USA):

15-: Of Monday 25^th July 1938:

Query

Dear Philosopher: Who was the author of the saying: “One man’s Mede is another man’s Persian”?—J. K.
I don’t know, but he should be immortal. This reminds me, somehow, that some 25 years ago I saw the pleasant variant of a well-known line: “Hell hath no fury like a woman corned.” It was my recollection that F. P. A. ⁴ said it. But recently I found it in the files of the Cleveland Leader back in Civil War time—in 1863, to be more exact. How much older is it? And how long has “corned” been a synonym for “ginned” or “pickled”?

⁴ Franklin Pierce Adams (1881-1960), known by his initials F. P. A., was a U.S. columnist.

16-: Of Saturday 13^th August 1938:

Home to Roost

I inquired a couple of weeks ago who was the originator of the brilliant wheeze, “One man’s Mede is another man’s Persian.” And now I have received an answer from F. P. A., of the New York Evening Post:
“It was said more than fifteen years ago, by George Kaufman, in a poker game.”
I put that in a separate paragraph, because I am anxious that credit may alight where credit is due.

17-: From the column Flashlights, by Thomas Jay, published in the North-Eastern Gazette (Middlesbrough, Yorkshire, England) of Wednesday 11^th January 1939:

A Munich scientist claims to have translated the ancient law of the Medes and the Persians. Even so it is still not clear whether one man’s Mede was another man’s Persian. (Help! Help!)