AC/DC co-founder and guitarist Malcolm Young died Saturday at home with his family by his side, having suffered from dementia for the past three years. He was 64.

One of rock’s most respected rhythm guitarists, Young had fully retired from the band in 2014, 41 years after founding the hard rock act with his brother Angus Young. He last performed with AC/DC in June 2010 in Bilbao, Spain.

In a statement, AC/DC wrote, "With enormous dedication and commitment he was the driving force behind the band. As a guitarist, songwriter and visionary he was a perfectionist and a unique man. He always stuck to his guns and did and said exactly what he wanted. He took great pride in all that he endeavored. His loyalty to the fans was unsurpassed."

Born in Scotland and raised in Sydney, Australia, Malcolm formed AC/DC in 1973 when he was 20. The band evolved in the 1970s from a hard-edged blues rock act into a heavy metal prototype for acts of the ‘80s; while they had several million-sellers, it was 1980’s Back in Black that made them international superstars. That album has been certified 22X platinum by the RIAA.

The Young brothers co-wrote every song they recorded, their best-known works being the anthems “Highway to Hell,” "For Those About to Rock (We Salute You)," "You Shook Me All Night Long" and “Dirty Deeds Done Dirt Cheap.” Onstage, Malcolm took the back seat to the antics of his brother dressed in a school boy outfits and the band’s lead singers, Bon Scott followed by Brian Johnson, but the riffs that drove thousands to pump their fists in the air were all his.

Angus said in a statement, "As his brother it is hard to express in words what he has meant to me during my life, the bond we had was unique and very special. He leaves behind an enormous legacy that will live on forever. Malcolm, job well done."

"Malcolm Young was one of the most important rhythm guitarists in the history of hard rock," reads a statement from Record Academy chief Neil Portnow. "As the co-founder and imaginative force behind AC/DC, Young created some of the most striking riffs that served as the backbone of the group's array of hit songs such as 'Highway To Hell,' 'You Shook Me All Night Long,' and 'Back In Black.' Young earned seven GRAMMY® nominations throughout his career, and was awarded the Best Hard Rock Performance GRAMMY for AC/DC's 'War Machine' for 2009. Young will be dearly missed, but remembered for his passion, pride, and unwavering dedication to his musical craft. Our thoughts go out to his family and friends during this difficult time."

Artists responded on Twitter to news of his death almost immediately. Eddie Van Halen called him “the heart and soul of AC/DC”; Ryan Adams referred to him as “the engine that roared behind the most powerful band in the world”; Kiss’ Paul Stanley called him “one of the true greats.” Def Leppard’s Joe Elliott tweeted “He was an incredible guitar player & the glue for that band onstage & off. RIP Malcolm, say hi to Bon" and Tom Morello called him “#1 greatest rhythm guitarist in the entire history of rock n roll.”