At 75, Charles Manson has spent more than half his life in prison for masterminding the notorious Helter Skelter killing spree that left actress Sharon Tate and six others dead in Los Angeles during the summer of 1969.

Manson spent his 75th birthday this week at the state prison in Corcoran, California, where he is isolated from the rest of the prison population. Some records indicate that Manson was born on November 12, but Manson's current associates and California corrections records indicate his birthday was on Wednesday, November 11.

While his appearance has changed significantly from the wide-eyed cult leader who appeared on the cover of Life magazine in 1969, Manson continues to wield influence over some who consider him a wizened messenger.