Emil Borer
Emil Borer (sometimes spelled Emile but known professionally as E. Borer) was a technician-watchmaker who ran the Aegler factory in Bienne, producer of watch movements for Rolex for decades.
By 1940, Borer was secretary of Manufacture des Montres Rolex Aegler SA under his grandfather Hermann Aegler (chairman) and Hans Wilsdorf (vice-chairman). In 1944, after Hermann Aegler's death, Emil Borer took charge of management of the Aegler factory even as Hans Aegler joined the administration along with Eduard Baumgartner and Gertrud-Hedwig Aegler.