Known as “the lady who swings the band,” jazz pianist, composer, arranger, and educator Mary Lou Williams (1910-1981) played in every era of jazz. She mentored and encouraged the pioneers of bebop, Thelonious Monk, and Bud Powell, in her Harlem apartment. She arranged for Benny Goodman, Dizzy Gillespie and Duke Ellington, and composed modern works including The Zodiac Suite. But in the 1950s, she left the jazz world, converted to Catholicism, then returned to the stage with her own soulful synergy of jazz and liturgical music, and taught at Duke University.

In her new book, Mary Lou Williams: Music for the Soul (Liturgical Press, Sept. 15) pianist and music scholar, Deanna Witkowski talks to PW about Williams’ embrace of the Catholic faith, and how it enriched her music and her life.

(This conversation has been edited for length and clarity.)

You write that, “Williams’s spiritual journey is also commonly reduced to a one-dimensional story emphasizing how her mid-life conversion to Catholicism made her somewhat of a religious fanatic.” What were some of the complex circumstances that led to her conversion?

ln 1954, she walked away from public performance, because she was questioning if her music was enough to help people. And when Charlie Parker died, I think she felt a sense of, not responsibility, but almost remorse, because she wasn't able to save him. When she first moved to Harlem in 1943, the Harlem riots happened, so she saw what was happening just outside her front door. So she (sought) solace in some kind of religion where she could still her spirit and her mind. And for her, in the beginning, that came from Our Lady of Lourdes, and churches in her Harlem neighborhood.

Who were the people who helped her convert to Catholicism?

There were (jazz critic and Catholic convert) Barry Ulanov and Dizzy and Lorraine Gillespie — Dizzy wasn't Catholic, but Lorraine became Catholic at the same time as Mary was received into the church —and a priest named John Crowley, who was a big fan of Mary Lou. I think Mary Lou, with the help of those four people, and also the priest who became her confessor, Father Anthony Woods, found a new sense of community, and people who were supportive of her.

Williams’ major religious-themed works include her opus dedicated to St. Martin de Porres, the 16th century, Afro-Peruvian priest, and her three large works; The Pittsburgh Mass, Mass for the Lenten Season, and Mary Lou’s Mass. What was unique about her music?

One thing that you see evolve in her sacred music, is how she thought about setting text. For example, in Creed, from her first Mass, The Pittsburgh Mass, the text is super long. It doesn't work very well. But perhaps from her being a devout Catholic, going to Mass regularly, and having those words become a part of her like daily prayer practice, I think she found more ways to set texts that became more natural as she went along. And so she made her liturgical music as accessible as possible, to share her faith.

Your forthcoming CD is entitled, Force of Nature. How does Williams influence you as a musician?

She influenced me in terms of how she saw the blues as not just spiritual music, but as something that could continue on in the future. And so her conception of what the blues is, and what that music encompasses, is larger than I thought previously. Mary Lou viewed blues (played in the jazz idiom) as very expansive music that was always supposed to be added to, and that's something that I try to bring in my music now.