Who is considered a modal jazz pioneer and what impact did they have on the development of jazz music?

John Coltrane is considered a modal jazz pioneer. He had a significant impact on the development of Jazz Music by popularizing the use of modal improvisation, which involved playing over a single scale rather than traditional chord progressions. This approach opened up new possibilities for musicians to explore different harmonies and melodic ideas, leading to the evolution of jazz music in the 1960s and beyond.