Complex sentence: He was captured by Prussians in 1760 during the Pomeranian Campaign and thereafter joined the Prussian Army, serving as a hussar officer for Prussia during the remainder of the Seven Years' War.
Split into simpler sentences: He was captured by Prussians in 1760 during the Pomeranian Campaign and thereafter joined the Prussian Army. Blücher continued to serve as a hussar officer for Prussia during the remainder of the Seven Years' War.