The 1st King's Mounted Rifles were a light cavalry regiment of the Royal Prussian Army from 1901 to 1918. When the Imperial German Army was reorganized as the Reichsheer, A Squadron/10th Horse became bearer of the regiment's tradition. The 1st King's Mounted Rifles belonged to the V Army Corps and was garrisoned in Posen. When the regiment was mobilized in 1914 it formed 10th Cavalry Brigade. Colonel-in-Chief of the regiment was Emperor William II, King of Prussia, hence the title King's.