It’s a sad day in the music world.

Adam Yauch, also known as MCA of the Beastie Boys, passed away today after a long battle with cancer. He told fans about his condition in July of 2009 via a YouTube video.

Starting out as the bass player in the Beastie Boys when they were a hard-core punk rock band in the early ’80s, he, along with drummer Michael Diamond (also known as Mike D) and guitarist Adam Horovitz (King Ad-Rock) began rapping and were signed to Def Jam Records, where their Rick Rubin-produced debut, 1986′s Licensed To Ill became the first hip-hop album to top the Billboard charts.

Read More: Beastie Boy Adam Yauch Loses Battle With Cancer