Playwrite Sir Peter Shaffer, who has died at the age of 90, was a giant of post-war British theatre, producing a string of dramatic - and cinematic - triumphs, including The Royal Hunt of the Sun, Equus and Amadeus, in the process bringing ritual, magic and music back into a theatre in danger of disappearing into kitchen sink naturalism. He made his theatrical debut with Five Finger Exercise (1958), a play in which an angry young outsider upsets a country weekend in Suffolk in the UK.In 1964 Shaffer's The Royal Hunt of the Sun, an epic about the Spanish conquest of Peru, became the first world premiere of a play by Laurence Olivier's recently established National Theatre. Conceived as "total theatre", in which mime, masks, music, magic and scenery contribute to the theatrical effect, it won ecstatic reviews and became famous for the mimed sequence following the stage direction, "The men then climb the Andes".Shaffer provided the National with three more hits - Black Comedy, Equus and Amadeus.A "whydunnit" based on a true story, Equus (1973) was a journey into the mind of a 17-year-old boy who, having blinded six horses with a metal spike in a frenzy of sexual frustration and semi-religious fervour ("Alan stabs out Nugget's eyes ... The horse stamps in agony," reads one stage direction), is referred to a psychiatric hospital.It transferred to Broadway, with Anthony Hopkins as the psychiatrist, and in 1977 was made into a film starring Richard Burton."In London," Shaffer recalled, "Equus caused a sensation because it displayed cruelty to horses; in New York, because it allegedly displayed cruelty to psychiatrists."In Amadeus (1979), meanwhile, Shaffer presented Mozart as a farting, giggling, foul-mouthed enfant terrible who drives his mentor, Salieri, to despair. Milos Forman's film version won eight Oscars including an award for Best Adapted Screenplay for Shaffer.Peter Levin Shaffer was born in Liverpool on May 15 1926, into a family of Orthodox Jews, five minutes after his twin brother, the playwright Anthony Shaffer.Despite Peter's claim that he was never jealous of his brother, letters written in the late 1960s laid bare Peter's frustration. The letters, discovered at Anthony's London home after his death in 2001, include such passages as: "I do feel threatened. As if my little Kingdom has been invaded, and I am no longer to be The Playwright, but again part of that faintly cute and annihilating 'Which one of them did it?'"In another letter, he implored: "Before it's too late? I beg you to take another name for writing." Anthony declined.Peter Shaffer, who was unmarried, was appointed CBE in 1987 and knighted in 2001.1926-2016..