Complex sentence: His unit took part in Operation Frühlingserwachen that failed, even though Peiper's unit inflicted large numbers of casualties, due to his aggressive style of command he lost many men and numerous old companions.
Split into simpler sentences: His unit took part in Operation Frühlingserwachen that failed. Although Peiper's unit inflicted a large number of casualties, due to his aggressive style of command he lost many men and numerous old companions.