Complex sentence: She reorganised the network with the help of her fiancé, Henri Cornioley, and it fielded over 1,500 members of the Maquis; they played an important role fighting the German Army during the D-Day landings.
Split into simpler sentences: She reorganised the network with the help of her fiancé, Henri Cornioley, and it fielded over 1,500 members of the Maquis. They played an important role fighting the German Army during the D-Day landings.