Happy birthday to Lady and the Tramp, which turns 60 years old today! That’s about 47 years older than the lifespan of the average pooch, in case you were wondering. To celebrate its 420th birthday (that’s in dog years, of course), here are 14 things you might not know about this canine classic.

1. It was inspired by a real dog named Lady.

In 1937, Disney writer Joe Grant showed Walt Disney some sketches he had done of his Springer Spaniel, Lady. Walt was impressed, and encouraged Joe to create a full storyboard. Like her fictional counterpart, the real-life Lady was learning how to deal with her owners’ new baby, which served as the main inspiration for Grant’s plot. In the end, Walt wasn’t thrilled with the storyline, and the idea was scrapped. Several years later, Disney came across a story by Ward Greene in Cosmopolitan titled “Happy Dan, the Whistling Dog." He believed that the two ideas could be combined into one to create a stronger story, and asked Greene to come up with one.

2. Walt Disney personally came up with the name “Tramp.”

In early drafts, the scruffy male dog was called Homer, Rags, Bozo, and even just Mutt. Walt himself scratched out “Mutt” in one of the scripts and penciled in “Tramp.” Ward Greene and the movie's distributors protested, feeling the name was a little too risque—but Walt Disney usually got his way, and this was no exception.

3. The real Tramp was a girl.

The writers and animators had plenty of inspiration for Lady, as some of the people involved with the film had spaniels they brought in as models. But the perfect mutt proved to be more elusive. One of the writers spotted the perfect happy-yet-bedraggled dog roaming around his neighborhood and tried to coax it over, but the dog was too quick. After failing to spot the dog again, the writer eventually checked with the city pound, where he found his perfect Tramp. Disney adopted the dog, who had apparently been just hours away from “taking the long walk,” and let her live in a private area behind Disneyland.

4. The Disney offices were filled with live animals for the animators to reference.

Not only were there dogs of every shape and size roaming around, but animator Woolie Reitherman kept a cage of rats next to his desk to reference for the rat fighting scene.

5. Walt thought the animators lost focus.

The idea for the story originated in 1937, and the rights to “Happy Dan” were purchased in the early 1940s—so why did it take until 1955 to get the movie out? Well, for one, Disney switched its focus somewhat during WWII, working on propaganda films. But at one point, Disney felt his animators had lost their feel for the characters. He removed them from work on Lady and the Tramp and had them switch to Sleeping Beauty for about six months. The change of scenery apparently worked; Disney believed that when the artists returned to the dogs, they “tackled the project with new enthusiasm.”

6. Roy Disney helped bring the movie back to life.

When the movie was put on the back burner due to WWII, it was almost forgotten completely. It wasn’t until 1952 that Roy O. Disney, Walt’s brother, encouraged him to start work on the movie again, outlining a plan to run the film in smaller first-run theaters only.

7. A gift Walt once gave his wife inspired a scene in the movie.

For Christmas one year, Walt bought his wife, Lillian, a Chow puppy. Instead of just trotting it out, Disney placed the puppy into a hatbox and presented his wife with the gift. She was disappointed at first—Lillian preferred to choose her own hats—but quickly recovered when the pup emerged. They named him Sunnee.

8. Many of the characters went through name changes.

The sinister Siamese cats had been part of the script since Joe Grant’s earliest versions, but instead of Si and Am, they were originally called Nip and Tuck. They belonged to an equally sinister mother-in-law, then called “Mumsie,” who later evolved into Aunt Sarah. And Jim Dear and Darling were once known as “Mr. and Mrs. Fred.”

9. Other characters didn’t make the cut at all.

Secondary characters that eventually got the axe included a pet duck that belonged to a neighbor and a canary named Trilby.

10. A song called “I’m Free” was also chopped.

After the Tramp character was further developed, it was decided that the tune no longer fit his roguish character as well as it once had. It was released as an extra when the movie came out on Blu-ray in 2012.

11. The spaghetti scene almost didn’t happen.

It’s now one of the most famous (and parodied) scenes ever, but Walt was against that cozy pasta scene. Though he wanted the dogs to have human emotions, he just couldn’t wrap his head around two dogs romantically sharing a strand of spaghetti. If you’ve ever watched your dogs fight over a plate of leftovers, you can imagine why. Disney eventually relented after animator Frank Thomas worked up a rough draft of how it might work.

12. Peggy Lee sued Disney for $25 million 30 years after the fact.

Singer Peggy Lee provided several voices for the film: both cats, Si and Am; Peg the dog; and Darling. She also wrote lyrics for the songs she performed in character. In 1988, Lee sued for $25 million in royalties and damages, claiming that her original contract said she would receive money for “transcriptions for sale to the public.” When the contract was written in the 1950s, of course, VHS didn’t exist. Lee’s argument was that VHS fell under the umbrella of “transcriptions,” and that Disney hadn’t given her anything for the millions of VHS tapes they later sold. ”I should think [Disney] would be willing to share, but I guess mice need a lot of cheese,” she later said. The court awarded Lee $3.83 million in 1991.

13. Trusty the Bloodhound almost didn’t make it.

Near the end of the movie, Trusty the bloodhound finds himself on the wrong end of the dogcatcher’s wagon. Though we later see him enjoying Christmas Day with his friends, it wasn’t supposed to end so happily. There are two stories as to why Trusty got a reprieve: one version is that Walt had gotten a lot of criticism for killing Bambi’s mother, and he wasn’t eager to repeat the experience. The other is that he saw Peggy Lee crying in the studio one day, and when he asked her why, she declared that the scene was just too sad. He argued that the movie needed the drama, but Lee pleaded with him to let Trusty live.

14. It was the first animated film to be made in CinemaScope.

The widescreen movie format was brand-new technology at the time. Though it was intended to help the viewer get a broad scope of landscapes and scenery, not everyone thought the format suited the movie so well. A New York Times critic reported, “The sentimentality is mighty, and the use of the CinemaScope size does not make for any less awareness of the thickness of the goo. It also magnifies the animation, so that flaws and poor foreshortening are more plain.”