At the end of 1758, the King instructed General Hans Joachim von Zieten to select the best officers for his Hussars from the whole army, and he selected Prittwitz as first lieutenant. On 12 August 1759, Prittwitz, then thirty-three years old, was promoted to the "Rittmeister" (cavalry captain). At a critical point in Battle of Kunersdorf, he saw Frederick standing on a small hill with the remnants of his body-guard—the Leib Cuirassier—determined to either hold the line or to die trying. With a 100-strong Hussar squadron, "Rittmeister" Prittwitz cut his way through the Cossacks and dragged the King to safety.