Phil Lesh, the founding bassist of the Grateful Dead, died Friday morning at the age of 84. a post on his official Instagram account.

The cause of death was not immediately clear.

Lesh, along with Jerry Garcia, Bob Weir, Ron McKernan and Bill Kreutzmann, formed the Grateful Dead in Palo Alto in 1965, and the band had a devoted following known as “Deadheads”.

In addition to playing bass, Lesh also sang high harmonies for the band and occasionally sang lead vocals, according to the New York Times. He also co-wrote some of the band’s most notable songs, including those that inspired adventurous songs like “St. Stephen” and “Dark Star” as well as more traditional tracks like “Cumberland Blues,” “Truckin'” and “Truckin'” . “Rainbox” according to the Times report

Lesh was born in Berkeley on March 15, 1940.

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