Francine Cocard says that
Gemen-Bourg, just like Soupert & Notting and the Ketten Bros., were breeders from Limpertsberg, a (then) suburb of Luxembourg-city.
According to tradition, it was in 1888 that Charles Gemen and his brother-in-law, Melchior Berg, established Gemen & Bourg at Luxembourg-Limpertsberg. However, the firm probably pre-dates even this. There is a copy of Gemen-Bourg's Autumn 1887 catalog in the Bibliotecheque Nationale-Luxembourg and it is thought that Charles Gemen himself might have been operating alone before that.
Charles Gemen was born on October 17, 1863, in Luxembourg, and died there as well on June 16, 1942. Melchior Bourg was born on April 29, 1861 and died on October 10, 1939. Melchior was married on May 24, 1897, to Charles' sister, Marie Francoise.
Around the year 1896, Melchior retired, but the firm continued to use the name Gemen & Bourg.
