Dethier was first introduced to the violin by his brother Gaston who originally trained as a violinist and was ten years older than Edouard.

[4] At seventeen Dethier already had a teaching post at the Brussels Conservatory and remained in the city for the next three years, living with his close friend and fellow violinist Paul Kochanski.

[5] In 1905, Gaston suggested that his brother join him in the United States, where he was a solo recitalist and the organist of the Church of St. Francis Xavier in Manhattan.

That same year Gaston had also been appointed the head of the organ department at the newly established Institute of Musical Art (later to become the Juilliard School).

[6] The couple had three children – Richard Emile, who died in 1928 at the age of fourteen, a younger son, Charles, and a daughter, Margot.