Throughout her career Madonna has been involved in writing and producing most of her own music. Madonna's early songwriting skill was developed during her time with the Breakfast Club in 1979. According to author Carol Gnojewski, her first attempts at songwriting are perceived as an important self-revelation, as Madonna said: "I don't know where [the songs] came from. It was like magic. I'd write a song every day. I said 'Wow, I was meant to do this'." Mark Kamins, her first producer, believed that Madonna is "a much underrated musician and lyricist." Rolling Stone has named her "an exemplary songwriter with a gift for hooks and indelible lyrics." According to Freya Jarman-Ivens, Madonna's talent for developing "incredible" hooks for her songs allows the lyrics to capture the attention of the audience, even without the influence of the music. As an example, Jarman-Ivens cites the 1985 single "Into the Groove" and its line "Live out your fantasy here with me, just let the music set you free; Touch my body, and move in time, now I know you're mine." Madonna's songwriting are often autobiographical over the years, dealing with various themes from love and relationships to self-respect and female empowerment. Her songs also speak about taboo and unconventional issues of their period, such as sexuality and AIDS on Erotica (1992). Many of her lyrics contain innuendos and double entendre, which lead to multiple interpretations among music critics and scholars. Madonna has been nominated for being inducted into the Songwriters Hall of Fame twice, for 2014 and 2016 ceremony. Rolling Stone listed Madonna at number 56 on the "100 Greatest Songwriters of All Time".
After its release, Evita garnered critical appreciation. Zach Conner from Time magazine commented, "It's a relief to say that Evita is pretty damn fine, well cast and handsomely visualized. Madonna once again confounds our expectations. She plays Evita with a poignant weariness and has more than just a bit of star quality. Love or hate Madonna-Eva, she is a magnet for all eyes." Madonna won a Golden Globe Award for Best Actress in Motion Picture Musical or Comedy for the role. She released three singles from the Evita soundtrack album, including "You Must Love Me" (which won an Academy Award for Best Original Song in 1997) and "Don't Cry for Me Argentina". Madonna was later presented with the Artist Achievement Award by Tony Bennett at the 1996 Billboard Music Awards. On October 14, 1996, Madonna gave birth to Lourdes Maria Ciccone Leon, her daughter with Leon. Biographer Mary Cross writes that although Madonna was often ill during the filming and worried that her pregnancy would harm the film, she reached some important personal goals: "Now 38 years old, Madonna had at last triumphed on screen and achieved her dream of having a child, both in the same year. She had reached another turning point in her career, reinventing herself and her image with the public." Her relationship with Carlos Leon ended in May 1997; she declared that they were "better off as best friends." After Lourdes' birth, Madonna became involved in Eastern mysticism and Kabbalah. She was introduced to Jewish mysticism by actress Sandra Bernhard in 1997.

Question: When did the relationship between the performer who writes and creates most of her own music and Carlos Leon end?
Answer: May 1997