This is the Prussian Treuen Kriegern Kreuz (True War Cross) awarded to combatants in the 1866 Austro-Prussian War. In that conflict Prussia and her allies from the Northern Confederation made short work of Austria, Württemberg, Bavaria, Saxony, Hannover, Nassau, and Braunschweig. Hannover, Braunschweig, and Nassau paid the ultimate price when they were absorbed into Prussia. Their territory was annexed into Prussia and came under direct Prussian rule. Their military also came under Prussian authority. The medal is in very fine condition and comes with a correct replacement ribbon.