Playwright Peter Shaffer is 80. “Shaffer hasn’t had a play open at the National for 21 years. But during the 1960s and 1970s he was responsible for four of the theatre’s biggest successes: The Royal Hunt of the Sun, Black Comedy, Equus and Amadeus. Hits were his department. It is said that during the dark days of the early ’80s, revenue from his plays kept the National in business.”