Complex sentence: Ziethen and Friedrich Wilhelm von Seydlitz, who had remained alert all night, organized the rear guard action that prevented the Austrians from falling upon the retreating Prussians, and by mid-morning, around 10 a.m., the Prussians retreated to the north-west.
Split into simpler sentences: Ziethen and Friedrich Wilhelm von Seydlitz, who had remained alert all night, organized the rear guard action that prevented the Austrians from falling upon the retreating Prussians. By mid-morning, around 10 a.m., the Prussians retreated to the north-west.