By Ruth Kinane
May 23, 2017 at 04:09 PM EDT

Ever since Taylor Swift said that 1989 cut “Bad Blood” was about someone in the music industry and not an ex-boyfriend, rumors swirled that the pop star was referring to Katy Perry. But neither singer explicitly commented on the supposed feud until Monday night, when Perry went on The Late Show With James Corden and confirmed she did indeed have a rocky relationship with Swift.

“Honestly, it’s really like she started it and it’s time for her to finish it,” Perry said of the fight, which started over backing dancers. She later claimed to have tried to talk to Swift, but to no avail. “It was a full shutdown and then she writes a song about me, and I’m like, ‘Okay, cool, cool, cool, that’s how you want to deal with it? Karma!'” Perry said, before admitting that she would quash the beef with Swift if the 1989 singer reached out to talk.

It wasn’t always like this. In fact, the two began exchanging friendly tweets in 2009, just five years before “Bad Blood” came out. Ahead, check out a timeline of Swift and Perry’s falling out.

July 2009

Eight years ago, Swift paid Perry a compliment via Twitter. “Watching the Waking up in Vegas video,” she wrote. “I love Katy Perry. I think I’m going to hang her poster on my wall now.” Perry responded, “You’re as sweet as pie! Let’s write a song together about the subject we know best… for my new record. It’ll be brilliant.” (The proposed collaboration never happened.)

September 2014

Between 2009 and 2014, the two publicly exchanged birthday wishes and tweets about cats, and Perry even stopped by Swift’s Fearless tour to perform “Hot N Cold.”

But by time 2014 rolled around, things changed. During an interview with Rolling Stone, Swift said her new song “Bad Blood” was about another woman in the music industry.

“For years, I was never sure if we were friends or not,” Swift said in the interview. “She would come up to me at awards shows and say something and walk away, and I would think, ‘Are we friends, or did she just give me the harshest insult of my life?'”

Swift explained to Rolling Stone that the artist “did something so horrible” and called her relationship with the unnamed singer akin to “straight-up enemies.” She added, “And it wasn’t even about a guy! It had to do with business. She basically tried to sabotage an entire arena tour. She tried to hire a bunch of people out from under me. And I’m surprisingly non-confrontational — you would not believe how much I hate conflict. So now I have to avoid her. It’s awkward, and I don’t like it.”

The day after the story appeared online, Perry tweeted, “Watch out for the Regina George in sheep’s clothing…” When she was later asked about the tweet, Perry said, “If somebody is trying to defame my character, you’re going to hear about it.”

May 2015

When the topic of bad blood between the pair came up once again in an interview with The Telegraph, Swift said: “I’m never going to talk about her in my interview. It’s not going to happen.” She went on to add that it was natural that she has “enemies.”

“It’s not real if someone appears to never have any issues with anyone,” she explained. “I have my friends. I have enemies.”

July 2015

After the MTV Video Music Awards announced that year’s slate of nominees, Nicki Minaj tweeted, “If your video celebrates women with very slim bodies, you will be nominated for vid of the year.” Minutes later Swift — seemingly taking Minaj’s comments as a personal attack on her “Bad Blood” nomination — responded: “I’ve done nothing but love & support you. It’s unlike you to pit women against each other. Maybe one of the men took your slot.”

The next day Perry chimed in, though didn’t mention Swift by name. “Finding it ironic to parade the pit women against other women argument about as one unmeasurably capitalizes on the take down of a woman…”

Minaj later clarified that her comments were not meant to target Swift in any way and the pop icons performed together (and hugged) when the awards show rolled around in August 2015. (Perry did not make an appearance that night.)

October 2015

In the fall of 2015, Swift’s comments to Rolling Stone about “Bad Blood” surfaced once more in a different interview. When a GQ reporter pointed out that even though she doesn’t explicitly name names in her songs, Swift does allow the public to decide who she’s targeting, Swift responded: “You’re in a Rolling Stone interview, and the writer says, ‘Who is that song about? That sounds like a really intense moment from your life.’ And you sit there, and you know you’re on good terms with your ex-boyfriend, and you don’t want him — or his family — to think you’re firing shots at him. So you say, ‘That was about losing a friend.’ And that’s basically all you say. But then people cryptically tweet about what you meant. I never said anything that would point a finger in the specific direction of one specific person, and I can sleep at night knowing that. I knew the song would be assigned to a person, and the easiest mark was someone who I didn’t want to be labeled with this song. It was not a song about heartbreak. It was about the loss of friendship.”

Swift went on to add, “So I don’t necessarily care who people think it’s about. I just needed to divert them away from the easiest target. Listen to the song. It doesn’t point to any one person or any one situation. But if you’d listened to my previous four albums, you would think this was about a guy who broke my heart. And nothing could be further from the truth. It was important to show that losing friendships can be just as damaging to a person as losing a romantic relationship.”

July 2016

After Swift’s relationship with Scottish D.J. Calvin Harris ended, it came out that Swift had actually co-written Harris’ hit with Rihanna, “This Is What You Came For,” under the pseudonym Nils Sjoberg. In a series of now-deleted tweets, Harris seemed to address the timing of the reveal. “Hurtful to me at this point that her and her team would go so far out of their way to try and make ME look bad at this stage though,” he wrote. In another tweet, he added, “I figure if you’re happy in your new relationship you should focus on that instead of trying to tear your ex bf down for something to do.” (At the time, Swift was dating actor Tom Hiddleston.)

Harris then name-dropped Perry. “I know you’re off tour and you need someone new to try and bury like Katy ETC but I’m not that guy, sorry. I won’t allow it,” he wrote. That day, after Harris’ tweets went viral, Perry tweeted out a GIF of Hillary Clinton shrugging.

She followed up by retweeting an old tweet from spring 2015, simply stating, “Time, the ultimate truth teller.”

September 2016

When a user tweeted at Perry, “Will you collab with Taylor swift,” she responded, “If she says sorry, sure!”

October 2016

While celebrating her 32nd birthday at a Kanye West concert in California, Perry recorded herself dancing to the lyric that references Swift in West’s song “Famous.” In a video posted to the singer’s Instagram story, she gets close to the camera and widens her eyes during the line, “I feel like me and Taylor might still have sex, why? I made that bitch famous.”

May 2017

In an interview with Entertainment Weekly, Perry talked about her new album, Witness, and was asked whether it contains a response to Swift’s “Bad Blood.” She commented that the upcoming record is “very empowered” and that “there is no one thing that’s calling out any one person.”

She added: “One thing to note is: You can’t mistake kindness for weakness and don’t come for me. Anyone. Anyone. Anyone. Anyone. And that’s not to any one person and don’t quote me that it is, because it’s not. It’s not about that. Honestly, when women come together and they decide to unite, this world is going to be a better place. Period end of story.

“But, let me say this: Everything has a reaction or a consequence so don’t forget about that, okay, honey,” she continued. “We got to keep it real, honey. This record is not about anyone else! This record is about me being seen and heard so that I can see and hear everyone else! It’s not even about me! It’s about everything that I see out there that I digest. I think there’s a healing in it for me and vulnerability. If people want to connect and be healed and feel vulnerable and feel empowered and strong, God bless and here it is.”

Soon after that story went online, Perry dropped new song “Swish Swish” featuring Nicki Minaj, which comes off as a diss track with lyrics like, “Don’t you come for me/ No, not today/ You’re calculated/ I’ve got your number/ Because you’re a joke/ And I’m a courtside killer queen.”

After the song’s release, Orange is the New Black actress and Swift’s friend Ruby Rose slammed Perry in a series of tweets. “‘Purposeful poop’ to ‘bomb a petit’ to a sloppy mess of writing over the top of Funkagenda..stop trying to make ‘Wit..I mean ‘fetch’ happen,” she wrote, later adding: “I’ve always stood up for the people I love and against things I think are cheap or mean spirited. That’s not new. You have to follow your ♥” Rose also took a shot at Perry’s sales numbers.

Just a few days later, Perry appeared on James Corden’s Late Late Show in a Carpool Karaoke segment, where she got candid about the rumored dispute for the first time.

“That’s true, there is a situation,” she responded when Corden asked about her history with Swift. “Honestly, it’s really like she started it and it’s time for her to finish it.”

During the segment, Perry confirmed the root cause of the feud was over backing dancers — and told her side of the story. “It’s so crazy!” Perry said. “Okay, so there are three backing dancers that went on tour with her tour, right? And they asked me before they went on tour if they could go, and I was like, ‘Yeah, of course. I’m not on a record cycle and get the work, and she’s great and all that. But I will be on a record cycle probably in about a year. So be sure to put a 30-day contingency in your contract so you can get out if you want to join me when I say I’m going back on.’ That year came up, right? And I texted all of them because I’m very close with them and I said, ‘Look, just FYI, I’m about to start. I want to put the word out there. They said, ‘Okay, we’re going to go and talk to management about it.’ And they did, and they got fired.”

Perry claimed Swift never talked to her about the dancers despite her attempts. “But what I want to say is that I’m ready for that BS to be done,” she said. “Now, there is the law of cause and effect. You do something, there’s going to be a reaction, and trust me daddy, there’s going to be a reaction. It’s all about karma, right? I think personally that women together — not divided, and none of this petty bullsh– — women together will heal the world.”

When Corden then asked: “Would it be enough to just receive a text from Taylor Swift that just said ‘the beef is off the grill?'” Perry answered: “100 percent.”

June 2017

In an interview with NME, Perry talked about her decision to address her history with Swift on Corden’s show. “I mean, I’m not Buddha — things irritate me,” she said before referencing “Bad Blood.” “I wish that I could turn the other cheek every single time, but I’m also not a pushover, you know? Especially when someone tries to assassinate my character with little girls [her fans]. That’s so messed up!”

She also acknowledged that her longtime collaborate Max Martin co-produced and co-wrote Swift’s “Bad Blood.” “I can’t speak for [Max], but he didn’t know [who ‘Bad Blood’ was about].’ I’m not supposed to tell him what he can and can’t do,” she continued. “I’m very fair; I’m super-duper fair and I’m not one of those people who’s like, ‘You can’t do that because I don’t like that person’. Just, like, you do you, make your own choices… I’m not his mother.”

This was one of multiple times Perry has discussed Swift on her press tour for Witness, while Swift has yet to make any comment on the situation — although she did make her entire catalog available on Spotify and other streaming services the same day Witness came out, a move many saw as a response to Perry.

After Witness‘ release, though, Perry sat down with Arianna Huffington for a conversation on The Thrive Global Podcast and talked about her desire to “let it go.” “I forgive her and I’m sorry for anything I ever did, and I hope the same from her,” Perry said. “And I love her, and I want the best for her. And I think she’s a fantastic songwriter, and I think that, you know, if we, both her and I, can be representatives of strong women that come together despite their differences, I think the whole world is going to go like, ‘Yeah, well we can do this.’ I don’t know. Like maybe I don’t agree with everything she does and she doesn’t agree with everything I do, but I just really truly want to come together in a place of love and forgiveness and understanding and compassion.”