Roddy McDowall was 41 in Escape from the Planet of the Apes when he played the character 'Cornelius'.
That was over 53 years ago in 1971.
In 1998 he died aged 70, starring in 166 films in his career, 107 of those after Escape from the Planet of the Apes was first released. If he were alive today he would be 95.
In Escape from the Planet of the Apes, I think Roddy McDowall looks: