[3] In early 1914 Georges Frey went to Berlin with a letter of recommendation from the Swiss composer Hans Huber to study with Henri Marteau at the Hochschule für Musik.

Owing to political turmoil he had to return to Paris prematurely, where he arranged to have a few last lessons with Berthelier who was already showing physical as well as mental symptoms of his brain tumour.

In January 1933 Georges Frey received an invitation from Albert Schweitzer to go to Strasbourg to hear the violinist Rolph Schroeder play the Bach Sonatas and Partitas with a curved bow.

The bond of friendship which now united him to Schweitzer stimulated his reflection on the interpretation of the polyphonic works for violin as well as his inventiveness in creating new models of the curved bow.

The outbreak of World War II put an end to this particularly fertile period of teaching and giving concerts: on 13 December 1940 the Frey family was expelled from Alsace, finding refuge in Aix-en Provence.