Much of Gielgud's theatre work in the later 1960s was as a director: Chekhov's "Ivanov" at the Phoenix in London and the Shubert in New York, Peter Ustinov's "Half Way Up the Tree" at the Queen's and Mozart's "Don Giovanni" at the Coliseum. One potentially outstanding acting role, Ibsen's Bishop Nicholas, fell through in 1967 when Olivier, with whom he was to co-star at the National Theatre in "The Pretenders", was ill. Gielgud played Orgon in "Tartuffe" and the title role in Seneca's "Oedipus" during the National's 1967–68 season, but according to Croall neither production was satisfactory. After this, Gielgud at last found a modern role that suited him and which he played to acclaim: the Headmaster in Alan Bennett's first play, "Forty Years On" (1968). The notices for both play and star were excellent. In "The Daily Telegraph" John Barber wrote, "Gielgud dominates all with an unexpected caricature of a mincing pedant, his noble features blurred so as to mimic a fussed and fatuous egghead. From the great mandarin of the theatre, a delicious comic creation."