Even without the Nazis, the story of pianists Toni and Rosi Grunschlag would have made compelling viewing. Filmed over 18 years by Will Wyatt and Todd Murray, we saw the sisters at home and abroad, both playing and reminiscing

The sisters were brought up in pre-war Vienna and by the time they were in their teens, had become recognised as musical prodigies. However, the Nazi occupation of Austria changed everything for the girls, now aged 15 to 21. Both parents and their brother had managed to escape to Palestine, leaving Toni and Rosi stranded in Vienna.

With the help of the virtuoso Bronislaw Huberman, who had left Vienna to set up the Palestine Philharmonic Orchestra, the girls managed to secure a visa out of Nazi Germany, and spent an idyllic few months in Hertfordshire before, sailing to New York, where they were re-united with their parents.

They lived in New York, in the same apartment, for the rest of their lives, with their twin grand pianos for company. They were lives devoted to each other and their music. Neither sister married. There were offers but as Rosi, pointed out, they did not live the kind of lives that allowed them to have dinner on the table for their husbands at 6pm every evening.

The Grunschlag sisters were a delight. They spoke the way they played piano – a constant back and forwards of idea, recollection and laughter, delivered in accents unaffected by their 70 years in the US.

Ultimately, their deaths were as synchronised as their lives. Both died at the age of 89. Rosi passed away just 19 days ago - three days after the sixth anniversary of hier sister's death. This film made the perfect tribute.