In 1968, surgeon H. Richard Hornberger—using the nom de plume of Richard Hooker—collaborated with writer W.C. Heinz to create the book MASH: A Novel About Three Army Doctors, based on his experiences with the 8055th Mobile Army Surgical Hospital during the Korean War. Two years later, Robert Altman used the book as the basis for a movie about the fictional 4077th unit (he cut the number 8055 in half.) Two years after that, M*A*S*H came to life again in the form of an 11-season television series that culminated in the most-watched series finale in television history (which occurred on this day in 1983). Here are some facts about the show that won't get you a Section 8.

1. ALAN ALDA AND JAMIE FARR SERVED IN THE U.S. ARMY.

Alda (Hawkeye Pierce) was in the Army Reserve for six months in Korea. Farr enlisted, and was stationed in Japan when Red Skelton requested his services on his USO Tour through Korea. Wayne Rogers (Trapper John McIntyre) joined the U.S. Navy for a time as a ship navigator. Mike Farrell (B.J. Hunnicut) served in the U.S. Marine Corps.

2. MCLEAN STEVENSON AUDITIONED FOR HAWKEYE, AND COMEDIAN ROBERT KLEIN TURNED DOWN THE ROLE OF TRAPPER JOHN.

Stevenson was convinced to take the role of Lt. Colonel Henry Blake instead. As for Klein, he denied a claim that he lived to regret the decision.

3. LARRY GELBART WROTE THE PILOT IN TWO DAYS FOR $25,000.

The veteran screenwriter had been living in London after growing tired of Hollywood, but he couldn’t pass up the opportunity to try to adapt Robert Altman’s movie for television audiences.

4. KLINGER WAS ONLY SUPPOSED TO BE IN ONE EPISODE.

He was also supposed to be gay. Jamie Farr’s character was changed to a heterosexual who cross-dressed to try to get himself kicked out of Korea. Allegedly, the Klinger character was influenced by comedian Lenny Bruce’s claim that he got discharged from the Navy for claiming to have “homosexual tendencies.”

5. ONLY THE NETWORK WANTED THE LAUGH TRACK.

Gelbart and executive producer Gene Reynolds were against the canned laughter; unfortunately CBS knew of no other way to present a 30-minute “comedy.” Gelbart and Reynolds did manage to get the network to agree to take out the laughing during the scenes in the operating room, and as the seasons progressed, the track got quieter and quieter. In the U.K., the BBC omitted the laugh track entirely.

6. CBS DIDN’T WANT ONE "UNPATRIOTIC" EPISODE.

An episode where soldiers stand outside in the freezing cold so that they can make themselves sick enough to be sent home was rejected by CBS. That soldier tactic was apparently actually used during the Korean War.

7. THE WRITERS CAME UP WITH AN INGENIOUS WAY OF DEALING WITH SCRIPT COMPLAINTS.

After growing tired of having to listen to cast members’ notes about their scripts, M*A*S*H writer Ken Levine and his fellow scribes changed their script on two occasions so that the actors were forced to pretend it was parka weather on 90- to 100-degree days on their Malibu ranch set. They took the hint and the “ticky tack” notes stopped.

8. WAYNE ROGERS WAS ABLE TO LEAVE THE SHOW BECAUSE HE NEVER SIGNED A CONTRACT.

Rogers was threatened with a breach of contract lawsuit. The problem was that he had never signed a deal, objecting to the standard contract given to TV actors when he had started playing Trapper John, particularly the “morals clause,” which he considered antiquated. Rogers said that aside from missing the cast—and his friendship with Alda in particular—he had no regrets about leaving the show after season three.

9. ALDA WAS THE ONLY ACTOR WHO WAS AWARE OF HENRY BLAKE’S FATE UNTIL MOMENTS BEFORE SHOOTING THE FINAL SCENE IN “ABYSSINIA, HENRY.”

Gelbart and Reynolds used the opportunity for McLean Stevenson wanting to leave after the third season to “make a point” about the “wastefulness” of war, and decided to kill off Henry Blake. After distributing the script without the last page and shooting all of the scenes written therein, Gelbart asked the cast to wait a few minutes before the start of the end-of-season wrap party and gave them each one copy of the final page, where Radar enters the O.R. and announces that Henry didn’t make it.

Larry Linville (Frank Burns) immediately remarked that it was “f***ing brilliant.” Gary Burghoff (Radar) turned to Stevenson and called him a son of a bitch, because he was going to get an acting Emmy for the episode. (He didn’t.) They then shot the scene in two takes. Gelbart and Reynolds claimed they received over 1000 letters from people upset over the ending. Reynolds also claimed that CBS was so unhappy with the decision that in at least one repeat airing, they cut out the final scene.

10. THE WRITERS RAN OUT OF NAMES.

During season six, there's an episode that features four Marine patients named after the 1977 California Angels infield. Throughout season seven, the patients were named after the 1978 Los Angeles Dodgers. Ken Levine didn’t just use baseball player's names though; in “Goodbye Radar,” Radar’s new girlfriend was named after one of Levine’s former lady friends, Patty Haven.

11. A METRIC TON OF FUTURE STARS MADE GUEST APPEARANCES.

Ron Howard played an underage Marine. Leslie Nielsen played a Colonel. Patrick Swayze portrayed an injured soldier with leukemia. John Ritter, Laurence Fishburne, Pat Morita, Rita Wilson, George Wendt, Shelley Long, Ed Begley Jr., Blythe Danner, Teri Garr, and even Andrew Dice Clay also all visited the 4077th.

12. THE SERIES LASTED MUCH LONGER THAN THE ACTUAL KOREAN WAR.

The series spent 11 years telling the story of Army doctors and nurses dealing with a three year, one month, and two day war.

13. THE SERIES FINALE IS STILL THE MOST WATCHED EPISODE OF TELEVISION IN AMERICAN HISTORY.

Seventy-seven percent of the people watching television in the United States on the night of Monday, February 28, 1983 were watching the two-and-a-half-hour series finale, “Goodbye, Farewell and Amen.” That was 121.6 million people. A company only had to pay $30,000 to run a 30-second commercial when M*A*S*H got started in 1972. For the series finale, a 30-second spot cost $450,000.

14. ALDA CO-WROTE 13 AND DIRECTED 31 EPISODES OF THE SERIES.

That 31 count includes the series finale. Alda was the first person to ever win an Emmy for acting, directing, and writing on the same program.

15. THERE WERE THREE SPINOFFS.

Trapper John, M.D., aired from 1979 to 1986 and was about Trapper John McIntyre’s present-day tenure as chief of surgery back in San Francisco (it didn’t star Wayne Rogers.) AfterMASH featured Col. Potter (Harry Morgan), Father Mulcahy (William Christopher), and Klinger (Jamie Farr) working at a veterans' hospital in Missouri right after the events of M*A*S*H; it was cancelled in its second season as it was unable to compete with The A-Team. W*A*L*T*E*R followed the new adventures of Walter “Radar” O'Reilly (Burghoff again), who became a St. Louis cop after losing the family farm and his wife (not Patty Haven) and attempting suicide. The pilot wasn’t picked up, and only aired once, and only in the eastern and central time zones, on CBS on July 17, 1984.

16. RADAR’S TEDDY BEAR WAS SOLD AND RETURNED TO BURGHOFF.

Burghoff said Radar’s teddy bear had been lost for 30 years until it suddenly turned up at an auction in 2005. A medical student bought it for $11,500, and promptly sold it back to Burghoff.

17. A CONSTRUCTION WORKER FOUND THE SHOW’S TIME CAPSULE ALMOST IMMEDIATELY.

In the series' penultimate episode, “As Time Goes By,” the characters bury a time capsule under the Fox Ranch. Two months later, the land was sold. Soon after, a construction worker found the capsule and got in contact with Alan Alda to ask what he should do with it. After he was told to keep it, Alda claimed the construction worker “didn’t seem very impressed.”