On How I Met Your Mother‘s last day of production a month ago, Dana Walden — chairman and CEO of 20th Century Fox TV, which produces the long-running series — HIMYM Finalewas meeting with the big boss, 21st Century Fox chairman and CEO Rupert Murdoch, in his office. She mentioned HIMYM was wrapping that day and, in the middle of their meeting Murdoch said, “I want to go over and say hallo.” He walked to the set and thanked creators Carter Bays and Craig Thomas, the cast and the crew “for all of the great work they have done.” “For a show to provoke that kind of response from Rupert, it speaks to how important that show has been to the company,” Walden said.

If such a gesture from the head of a global conglom might come as a surprise, it is probably because HIMYM, which wraps its nine-season run tonight on CBS, has flown largely under the radar. HIMYM hasn’t been a blockbuster ratings hit like The Big Bang Theory, hasn’t made headlines with a record-breaking syndication cbs-logo__120711164808__121116195436__130108233101__130716162250__130926192712__131121001522deal like 2 Broke Girls, and hasn’t been an awards darling like Modern Family, never landing an Emmy in the major categories. But it broke ground, pushing the limits of the traditional multi-camera sitcom with a new production model and heavy serialization that helped it attract younger (18-34) viewers, something very few multi-cam comedies have been able to do in the past decade as young audiences have been largely shunning the format in favor of edgier single-camera fare.

Multi-camera comedies had tried employing shorter scenes before, most notably NBC’s Seinfeld. But Bays and Thomas’ pilot script for How I Met Your Mother called for a pace that had not been achieved before. It included a whopping 59 scenes, plus freeze frames with narration, whip pans, a split screen scene and a montage. That’s not how you normally see in a multi-camera sitcom, which is what CBS had bought in HIMYM. But then, Carter and Bays didn’t quite know normal. The young writers were recent transplants to Los Angeles and primetime after a stint at CBS’ Late Show With David Letterman. They had only worked for a couple of very short-lived comedy series and had never developed before HIMYM. “This was new to them, and they didn’t know the limitations of what they can and cannot do, so they wrote what was in their heads,” Walden said.

Karaoke Fundraiser to Benefit The Art of ElysiumThe innovative hybrid format, which involves filming with no live audience and laying on a laugh track by screening the completed episode to a group of people, was born out of necessity. At a staff meeting early in the 2005 pilot season, a comedy production executive brought up the fact that filming Bays and Thomas’ pilot script in front of a live audience would be frustrating for those in attendance, because, pamfrymandue to the large amount of very short scenes, they would spend most of their time watching sets being re-lit. The idea for the hybrid model was hatched at that meeting, with the pilot’s director Pam Fryman quickly coming on board. (She would go on to direct 194 of the series’ 206 episodes.) Initially, the plan was to only use it on the pilot and switch to a traditional multi-cam filming in front of a live audience for the series. However, the following scripts “came with same degree of difficulties, and, talking to Pam, we felt strongly that the tone of the show was so special that we should try to capture it we as it did in the pilot, not turn it in just another live-audience multi-camera show,” Walden said.

The HIMYM model has been hailed as a fresh new twist on the sitcom format that combines the economic advantages of the lower-budget muti-cam with the dynamic of a single-camera. Networks and studios have attempted to use it for a number of comedy projects since, but none has been as successful as HIMYM.

Also difficult to replicate has been HIMYM‘s serialized nature. HIMYM is a comedy with a big overarching mystery at the center that took eight seasons to unfold. A number of comedies have attempted a serialized format — most recently ABC’s Mixology — but none has succeeded. How meticulously was the HIMYM mother storyline planned? Fearing the young actors playing Ted’s feature kids would be too grown-up by the end, the creators filmed a scene with them during the second season that will be used in the series finale tonight. Bays and Thomas also came very close to the length of the show they’d been shooting for from the very start — eight seasons. (In support of Bays and Thomas’ original plan, fans have been griping about the current Season 9, which came after a last-minute deal with Jason Segel, meaning that Bays and Thomas probably were right on the money believing that their idea would best play out over eight seasons.)

Related: PaleyFest: ‘How I Met Your Mother’ Creators Dodge Finale Questions

himym4Back during Season 2 when Bays and Thomas filmed the finale scene, HIMYM was heavily on the bubble and at serious risk for being cancelled. The show’s soft ratings were a source of frustration for CBS executives as it had shown a lot of promise. The pilot for HIMYM tested through the roof, and, with its young ensemble, the show was hailed as the next Friends during CBS’ 2005 upfront. But it didn’t pop. Maybe because it was different from CBS’ other, more traditional sitcoms (HIMYM was launched sandwiched between The King Of Queens and Two And A Half Men), it didn’t click with audiences for its first season. And its second. But, despite sluggish ratings, HOW I MET YOUR MOTHER: SEASON 3 GALLERYCBS kept renewing the series, which was championed by top executives Nina Tassler and Nancy Tellem. Then, midway through Season 3, the writers strike hit. With production screeching to a halt, all scripted series went on lengthy hiatuses. Whatever hope for third-season momentum HIMYM may have had was gone.

After the strike, CBS made a scheduling change, moving HIMYM from 8 PM to 8:30 PM, with plucky freshman Big Bang Theory as a lead-in. 20th TV also stepped up efforts to secure another renewal. “We had been pushing for stunt casting opportunities, anything to get more viewers to sample the show,” 20th TV chairman and CEO Gary Newman said. The studio’s casting executive Stepahnie Herman pitched the idea of Britney Spears, at the time the hottest tabloid celebrity who was trying to get her life back together following her epic meltdown. Herman was friendly with her manager and reached out. It turned out that Spears was a fan of HIMYM and was interested in a guest star role on it. The filming of the episode was a spectacle, with helicopters buzzing overhead and throngs of paparazzi at the studio’s barricaded gates for a glimpse of the troubled star. Whether it was the massive publicity surrounding Spears’ stint on the show or the new time slot or both, HIMYM returned from a three-month break with a season high in 18-49. The following week, the episode featuring Spears set a series high in 18-39 (4.5) and a season high in total viewers (10.8 million) “Ratings exploded, and the show never looked back, going onto a long and successful run on CBS and in syndication,” Newman said.

Related: ‘How I Met Your Mother’ Spinoff Officially A Go At CBS