Patrick Stewart died in Los Angeles on Wednesday.

He was 86 years old.

His spokesperson said he had a "brief and poignant journey" with Alzheimer's disease and Lewy Body Dementia.

Stewart was known for playing Capt. Jean-Luc Picard in "Star Trek."

He also played Professor Charles Xavier in the "X-Men" films.

His death led to many tributes from acting colleagues and Marvel Studios.

William Shatner is a fellow "Star Trek" alum.

He called Stewart a friend, a colleague and a magnificent actor.

He said Stewart brought intelligence, grace and humanity to everything he did.

He said Picard stood for the best of us.

Hugh Jackman was Stewart's "X-Men" co-star.

He said on Instagram that they had lost one of the greats of stage and screen.

He called Stewart a tremendous friend.

He said he learned so much from him.

George Takei is another "Star Trek" alum.

He said fans around the world mourn an irreplaceable legend.

He said Stewart took the Enterprise to places it had never gone before.

He said Stewart inspired a new generation of star-gazers.

Marvel Studios said it was deeply saddened.

It said Stewart defined Charles Xavier for generations of fans.

It called him a singular talent and a true gentleman.

It sent condolences to his wife Sunny, his children and his friends.