Patrick Stewart, the British actor whose calm demeanor and steely strength led the Star Trek television franchise into its next generation, died Wednesday at age 86. The actor suffered from Alzheimer’s disease and Lewy body dementia.

“We announce with great sorrow the passing of Sir Patrick Stewart yesterday at his home in Los Angeles, in the care of his beloved wife Sunny,” a Thursday post on Stewart’s Instagram account read in part. “We will forever cherish the peaceful ease and reflection on his face, an enduring reminder of his invincible grace.”

Through a long career, Stewart starred in everything from Shakespeare productions to superhero films, but his role as Captain Jean-Luc Picard in Star Trek: The Next Generation is firmly cemented in entertainment culture. Show creator Gene Roddenberry didn’t at first think Stewart, who was bald, could play the virile captain he had envisioned for the new Star Trek series.…