Jonathan Mayers, a concert promoter who co-founded the music festivals Bonnaroo and helped create Outside Lands as a principal at Superfly Entertainment, has died. He was 51. The cause of death is as yet unknown. The news arrives as the three-day Bonnaroo Music and Arts Festival is set to kick off Thursday with headliner Luke Combs.

Jonathan Mayers, the founder of music festivals like Bonnaroo and Outside Lands, has died. He was 51. No cause of death was released.

Mayers' flagship events helped usher in the modern era of American music festivals. No cause of death was given.