Complex sentence: The French had made no further progress and had lost 12,000 men (P. Denniee. Itineraire de l'Empereur Napoleon. Paris, 1842) though casualties and even the date of the main fighting vary according to source.
Split into simpler sentences: The French had made no further progress and had lost 12,000 men (P. Denniee. Itineraire de l'Empereur Napoleon. Paris, 1842). Casualties and even the date of the main fighting vary according to source.