There have been many gloriously bitter celebrity feuds over the years, but few have captured the public's imagination quite like the longstanding beef between Katy Perry and Taylor Swift.
Katy and Taylor's war was a cold one waged with subtle invective and veiled insults.
Despite the mostly passive nature of the aggression, there was never any doubt about the singers' animosity toward one another.
Others say the rivalry had to do with the fact that both women dated John Mayer (at different times).
We may never know for sure, but whatever the cause, the bad blood was so intense that years after their initial spat, these two are still not on speaking terms.
So you can imagine our surprise this week when Robert Pattinson was spotted hanging out with Taylor.
Perry and Pattinson dated briefly and they've remained close friends in the years since their fling came to an end.
These days, Katy is engaged to Orlando Bloom and Taylor is dating Joe Alwyn, so there's no risk of this turning into another Mayer situation.
But still, fans were caught off-guard by reports that R-Pattz and girlfriend Suki Waterhouse were spotted on a double date with Taylor and Joe.
Many expected that this development would reignite the dormant beef between Katy and Taylor, but remarkably, it seems Perry is taking a Zen-like approach to the news.
“Katy is cool if Rob happens to go out with Taylor in social settings and [feels that] it’s none of her business,” a source close to the situation tells Hollywood Life.
“She and Rob have been friends forever and she isn’t going to make something out of nothing."
Yes, it seems we're dealing with a more mature Katy these days.
In fact, the insider says that while Katy won't be burying the hatchet with Taylor anytime soon, she no longer harbors an intense, burning hatred for her fellow pop icon:
"Katy’s issues with Taylor have tempered anyways and Katy is actually looking to the future and not the past with that feud," says the insider.
"She has no ill will toward Rob for the dinner date, and she won’t if he does it again.”
It's a far cry from the days when Karlie Kloss hung out with Perry and got cut off by Swift as a result.
We're proud of Katy and Taylor for moving on from the pettiness -- but we'd be lying if we said we most miss their wildly entertaining feud.