In summer 1967, Kenneth MacMillan had hoped to end his first season as ballet director in West Berlin with a new production of The Sleeping Beauty. When this had to be delayed, he substituted a triple bill consisting of Diversions, Solitaire and a new work, Anastasia.

MacMillan had been powerfully struck by the case of Anna Anderson, a psychiatric patient in Berlin in the 1920s, who had had tried to commit suicide by jumping into a canal. She had claimed to her rescuers to be the Grand Duchess Anastasia of Russia, daughter of the last Tsar, Nicholas II. Somehow, she told those who would listen, she had escaped the massacre of the Imperial Russian family by the Bolsheviks at Ekaterinburg in 1918. For MacMillan, Anna Anderson’s story opened a rich seam; compelling material for a ballet on psychosis and memory.

In a programme note MacMillan described his heroine as “the woman believed to be Anastasia” and the doubt thereby left hanging is what gives the ballet its dramatic tension. The setting is a mental hospital, where the dowdy Anna sits on her bed attended by nurses. First she struggles to recall who she is, and, having remembered, she struggles to persuade others of her identity. A chorus of formidable Russian émigré women inspect her, shake their heads and laugh derisively. She is shown old film of pre-Revolution Anna and suddenly, seeing a child’s face, she is animated. The memories that are evoked are not in sequential time, but are kaleidoscopically episodic; children at play; a sinister monk who might be Rasputin; a flurry of soldiers and an execution; flight, huddled on a wheelbarrow; life with a man who fathers her child; another shooting; another flight. But by the close, Anna knows she is Anastasia and a hospital bed becomes in her mind a stately carriage, on which Anna stands high. As the stage resolves, Anna on her bed makes a royal progress in what seems triumphant self-realisation.

MacMillan broke new ground when he made Anastasia. The movement is strongly expressionist and for one critic, the ballet recalled Martha Graham’s dance dramas. Another innovation was the use of silent film, which was projected on two curving screens, to animate the action on stage below. MacMillan’s choice of score was apposite. Martinu’s sixth symphony was itself an act of recollection, written several years after the composer had had a serious head injury; in writing it Martinu was seeking to summon up - and makes sense of - a confused past. In addition, MacMillan used electronic music created in a studio at the Technical University of Berlin to set the opening scene. The projected film of the Tsar’s family came from a documentary From Tsar to Stalin. Because MacMillan was spending so heavily on the delayed production of The Sleeping Beauty, there was almost no money for designs. This meant that the designer Barry Kay had to improvise and use costumes from the Deutsche Oper wardrobe. The only luxury was stage rehearsal time, vital for Anastasia because of the production’s reliance on lighting and projected film.

In the event, the ballet was successful with audiences and warmly praised both in the Berlin papers and by those critics who had travelled from London. For John Percival of The Times, whose review appeared the morning after the premiere, Anastasia was “unusual, daring and tremendously stirring” and on a bolder scale than anything MacMillan had previously attempted. “To hold the ballet together”, he wrote, “demands a powerful effort from its protagonist, which Lynn Seymour makes magnificently. To add to her difficulties, she has to begin one duet holding her baby, and end another on a revolving stage, but nothing daunts her for a moment.”

The Guardian’s critic, Craig Dodd, also praised Seymour’s performance, both as dancer and actress, noting thatAnastasia was “effectively MacMillan’s first attempt at a piece of ‘total theatre’”. Dodd also singled out Barry Kay’s designs. “He has marshalled all the effects into an exciting stage picture, a final masterstroke being a line of tailors’ dummies wearing the clothes of the Tsarist family, mute echoes of Anastasia’s past.”

In 1971, when MacMillan had returned to London as director of The Royal Ballet, the one-act Anastasia he had made in Berlin became the third act of a full-length ballet. It was not until 1994 that DNA evidence proved that Anna Anderson could not have been a member of the Russian Imperial family. Even if she wasn’t who she claimed, MacMillan thought her story compelling. As he told Clement Crisp in 1971, “I found in her story a theme that has sometimes appeared in my work before; the Outsider figure. Anastasia seems to me to be a supreme example of this.”

• First performance: Deutsche Oper, Berlin, 25 June 1967

• Company: Ballet of the Deutsche Oper

• Cast: Lynn Seymour, Rudolf Holz, Vergie Derman, Gerhard Bohner

• Music: Bohuslav Martinu, Symphony No. 6 (Fantaisies symphoniques); electronic score, Fritz Winckel and Rudiger Rufer

• Design: Barry Kay

• Benesh notation score: Monica Parker (1968), Working score, one act version