Answer
Peiper commanded the 1st SS Panzer Division's 2nd SS Panzer Regiment from February 1943 to September 1944, when he was promoted to command the 1st SS Panzer Division itself. The 2nd SS Panzer Regiment had been the division's spearhead during its successful campaigns in Russia in 1941 and 1942, and it continued to play a leading role in the division's operations in France and Belgium in 1944.