Dr. Gabriel Ersler (1913-2005) was born in Woclawek, Poland and studied medicine in Berlin until 1933 and in Bern, Switzerland until 1936. He went to Spain in 1937 and became a staff doctor at the Centre de Instruccion de Madrigueras, Albacete. He then became chief of the medical unit of the 13th International Brigade. As an exile in France after the Spanish Civil War he joined the anti-fascist Resistance. In 1956 he moved from the Soviet Union back to his native Poland, where he became disillusioned by the resurgence there of anti-semitism and, in 1968, emigrated to France. By the 1970s he was living in Israel and practicing there as an eye specialist. He traveled widely in Europe with his first wife, Conchita; after her death he married again, to Janine Szurek, and lived in his later years in France.

He embarked on a major research project to create a biographical directory of foreign (and especially Jewish) volunteers in the medical units of the International Brigades. In the course of this work he corresponded with, and eventually visited, Fredericka Martin, who was carrying out related research from her home in Cuernavaca, Mexico. He also corresponded with Victor Berch, archivist of the Lincoln Brigades collections at Brandeis University. Ersler published articles on the medical service in several languages, sometimes as G. E. Sichon or Gabriel Ersler Sichon, incorporating his mother's maiden name in the Spanish style.