Complex sentence: Lehmann was recommended for the Knight's Cross by Theodor Wisch on account of his leadership of a battle group in the Zhitomir area of the Ukraine during December 1943.
Split into simpler sentences: Lehmann was recommended for the Knight's Cross by Theodor Wisch. The award of the Knight's cross was for his leadership of a battle group in the Zhitomir area of the Ukraine during December 1943.