February to June 1964. With the RSC he also played "the gruelling role" of Father Riccardo Fontana in Rolf Hochhuth's controversial play The Representative at the Aldwych in December 1963. Later theatre work He enjoyed a career breakthrough at the Mermaid Theatre in April 1968 as Fr. William Rolfe in Hadrian the Seventh, winning his first Evening Standard Award as Best Actor for the London production and a Tony nomination after the transfer to Broadway. At the Royal Court in August 1970, McCowen was cast to play the title role in Christopher Hampton's sophisticated comedy, The Philanthropist. If a philanthropist is literally someone who likes people, McCowen's Philip was a philologist with a compulsive urge not to hurt people's feelings – the inverse of Molière's The Misanthrope. Following enthusiastic reviews the production played to packed houses and transferred to the Mayfair Theatre where it ran for a further three years, making it the Royal Court's most successful straight play. McCowen and his co-star Jane Asher went with it to Broadway in March 1971 where he won the 1971 Drama Desk Award for Outstanding Performance. His next big successes were in National Theatre Company productions at the Old Vic. In February 1973 he co-starred with Diana Rigg in Molière's The Misanthrope for which he won his second Evening Standard award; followed in July 1973 by the role of psychiatrist Martin Dysart ("played on a knife edge of professional skill and personal disgust by McCowen", according to Irving Wardle reviewing for The Times) in the world premiere of Peter Shaffer's Equus. McCowen devised and directed his own solo performance of the complete text of the St. Mark's Gospel, for which he received international acclaim and another Tony nomination. It opened first at the Riverside Studios in January 1978 before beginning a long West End season at the Mermaid Theatre then at the Comedy Theatre. Taking the production to New York, he appeared at the Marymount Manhattan and Playhouse theatres. Christopher Hampton's stage adaptation of George Steiner's novel The Portage to San Cristobal of A.H. at the Mermaid in 1982 gave McCowen a great final speech, an attempted vindication of racial extermination delivered by Adolf Hitler, which for Guardian critic Michael Billington was "one of the greatest pieces of acting I have ever seen: a shuffling, grizzled, hunched, baggy figure, yet suggesting the monomaniac power of the Nuremberg Rallies, inhabiting the frail vessel