 Complete the following phrase:  He was succeeded by his son, Frederick William III 17971840, who involved Prussia in the disastrous Fourth Coalition. The Prussian Army was decisively defeated in the battles of Saalfeld, Jena, and Auerstedt in 1806. The Prussians famed discipline collapsed and led to widescale surrendering among infantry, cavalry, and garrisons. While some Prussian commanders acquitted themselves well, such as LEstocq at 