Complex sentence: During the Napoleonic Wars, the German struggle against the occupying French forces was significantly symbolised by the colours of black, red, and gold, which became popular after their use in the uniforms of the Lützow Free Corps, a volunteer unit of the Prussian Army.
Split into simpler sentences: During the Napoleonic Wars, the German struggle against the occupying French forces were significantly symbolised by the colours of black, red, and gold. This was largely attributed to the uniforms of the Lützow Free Corps, a volunteer unit of the Prussian Army.