What was going on, in Europe, c. 1200 BC?
Massive population migrations, the collapse of the Hittite Empire, Egypt’s invasion by the “Sea Peoples”, etc. If there was a period where you’d expect large-scale war in Germany, this would be it.
Might I suggest severe fluctuations in climate could have initiated the migrations, the collapse of the Hittite Empire, and the invasion of the eastern Mediterranean coastline by the “Sea Peoples”?
According to Brian Fagan in The Long Summer: How Climate Changed Civilization, there was a very long, hot dry period between 2200 to 1200 bc. Beginning on page 177, he claims a widespread drought in 1200 bc affected much of eastern Europe and the Middle East.