Who was the first female jazz instrumentalist to gain significant prominence?

The first female jazz instrumentalist to gain significant prominence is indeed Mary Lou Williams. She was a pioneering figure in jazz, known for her outstanding skills as a pianist, composer, and arranger. Williams played a crucial role in the development of jazz, bridging the gaps between various styles like swing, bebop, and modern jazz.

Her contributions are notable not only because she was a talented musician but also because she actively influenced and collaborated with many other musicians during her career. Williams was not only recognized for her playing but also for her compositions and arrangements that were performed by prominent orchestras of her time. This level of recognition and influence set her apart as a trailblazer for female musicians in a predominantly male-dominated field.

In contrast, while Billie Holiday, Ella Fitzgerald, and Nina Simone were remarkable vocalists who made significant contributions to jazz, they are not primarily known as instrumentalists. Their impact on jazz involves their vocal artistry rather than instrumental prominence, which differentiates them from Mary Lou Williams in the context of this question.