Complex sentence: In the beginning, this helmet was simply an aluminium alloy version of the M1943 Stahlhelm used by the Wehrmacht, standardized in 1956 and normed in 1964 by DIN 14940.
Split into simpler sentences: In the beginning, this was simply an aluminium alloy version of the M1943 Stahlhelm used by the Wehrmacht. It was standardized in 1956, and normed in 1964 by DIN 14940.