Holst wrote the concerto for them .
On 3 April 1930 , she and her sister gave the first performance of the Concerto for Two Violins of Gustav Holst , at a Royal Philharmonic concert at the Queen 's Hall , under the direction of Oskar Fried .
Gustav Holst wrote the concerto for them .
On 3 April 1930 , she and her sister gave the first performance of the Concerto for Two Violins of Gustav Holst , at a Royal Philharmonic concert at the Queen 's Hall , under the direction of Oskar Fried .