Here's what happened:
* Contract Dispute: Doherty and the producers had a contract dispute over her salary. She felt she was being underpaid compared to her co-stars Holly Marie Combs and Alyssa Milano.
* Creative Differences: There were also reports of creative differences between Doherty and the producers, including disagreements over the direction of Prue's character.
* Departure: In the season 3 finale, Prue was tragically killed off the show. This was done to accommodate Doherty's departure and provide a dramatic exit for her character.
Doherty's departure was a major event in the show's history, and it marked a significant change in the dynamic of the Halliwell sisters. The introduction of Rose McGowan as Paige Matthews helped to fill the void left by Prue, but her absence was definitely felt by fans.
Despite the difficult circumstances surrounding her departure, Doherty has spoken fondly about her time on Charmed and her experience working with her co-stars. She has also expressed gratitude to the fans for their continued support.