CALGARY — Legendary British actor Sir Patrick Stewart, best known for portraying Captain Jean-Luc Picard in Star Trek and Professor Charles Xavier in the X-Men franchise, has died at the age of 86.Stewart died Wednesday at his home in Los Angeles following a battle with Alzheimer's disease and Lewy body dementia, according to a statement shared on his official X account Thursday. His longtime spokesperson, Kelly Bush Novak, confirmed the news, describing his illness as a brief but difficult journey.Stewart was surrounded by family and friends during his final hours, with loved ones gathering for live music, prayer, laughter and tears.The statement also described the peaceful expression on Stewart's face at the time of his passing, saying it would remain a lasting reminder of the grace he demonstrated throughout his life..Born July 13, 1940, in Mirfield, West Yorkshire, England, Stewart developed an interest in acting at a young age.He attended the Bristol Old Vic Theatre School before establishing himself as a stage performer, eventually joining the prestigious Royal Shakespeare Company.Stewart spent years performing classical theatre, appearing in productions of Shakespeare's Macbeth, Hamlet and other major works before gaining international recognition through television.His career changed dramatically in 1987 when he was cast as Captain Jean-Luc Picard in Star Trek: The Next Generation.The series ran for seven seasons, introducing Stewart to audiences around the world and establishing Picard as one of the franchise's most recognizable characters.Stewart subsequently reprised the role in several Star Trek films and returned decades later for the television series Star Trek: Picard, which concluded in 2023..In 2000, Stewart took on another defining role when he appeared as Professor Charles Xavier in the first X-Men film. His portrayal of the wheelchair-using telepathic leader of the X-Men introduced him to a new generation of moviegoers.He continued playing the character for more than two decades, appearing in several installments, including X2: X-Men United, X-Men: The Last Stand, Logan and Doctor Strange in the Multiverse of Madness.His long-running association with the Marvel franchise earned him recognition from Guinness World Records for his extensive portrayal of the character.Beyond his blockbuster roles, Stewart maintained a successful theatre career and received numerous honours for his contributions to the performing arts.He earned a Grammy Award in 1996 for his narration of Peter and the Wolf, received multiple Emmy nominations and was awarded a star on the Hollywood Walk of Fame.In 2010, Queen Elizabeth II knighted Stewart for his services to drama, recognizing his contributions to British theatre and entertainment..Stewart's death has brought attention to the two neurological conditions he reportedly battled during his final months, Alzheimer's disease and Lewy body dementia.Alzheimer's disease is a progressive neurological disorder and the most common cause of dementia. It gradually damages brain cells, affecting memory, reasoning, communication and the ability to perform everyday activities.As the disease progresses, individuals may experience increasing confusion, difficulty recognizing familiar people and eventually require assistance with basic daily tasks.Lewy body dementia is a separate progressive neurological condition caused by abnormal deposits of a protein known as alpha-synuclein in the brain.According to the Alzheimer Society of Canada, the condition accounts for approximately five to 10% of dementia cases and can affect thinking, movement, sleep and behaviour.Unlike Alzheimer's disease, which commonly begins with memory difficulties, Lewy body dementia can initially cause significant fluctuations in alertness, visual hallucinations, disturbed sleep and movement problems resembling Parkinson's disease.There is currently no cure for either condition, although medications and supportive therapies can help manage certain symptoms.