Lou Koster

Her maternal grandfather, Franz Ferdinand Bernhard Hoebich (1813–1900), who was born in Silesia, was the conductor of the military band in Echternach from 1842.

[3][4] It was her grandfather who taught Lou Koster not only to play both the violin and the piano but also elementary music theory.

At a time when girls in Luxembourg could only study music privately, Koster proved to be a gifted student.

After her grandfather died in March 1900, her mother continued her music education until she was 15, when she was sent to spend two years with her aunt Anna Hoebich in Paris so that she could learn to speak French.

[3] It was only in 1906, when she was 17, that Koster was able to attend the newly opened Luxembourg Conservatory, where she was able to continue her violin and piano studies, primarily under Joseph Keyseler (1879–1953) and Marie Kühn-Fontenelle (1875–1952).

[3] The Koster daughters began to earn their living from music at an early age, even before the First World War.

They accompanied silent films on Sundays and holidays, playing the violin (Lou) and the cello (Lina and occasionally Laura) and performed in the capital's concert cafés.

In connection with the centenary celebrations for Luxembourg's independence in 1939, her marches "La Joyeuse" and "Keep Smiling" were performed, as well as a fantasy from her An der Schwemm.