Final answer:
The 30 years war led to the formation of new national identities in Europe, as it deepened religious divisions and fueled nationalistic sentiments.
Step-by-step explanation:
The 30 years war had a significant influence on the development of national identities in Europe. The war was marked by conflicts between Protestant and Catholic powers, which deepened religious divisions and fueled nationalistic sentiments. These divisions led to the formation of new national identities, as people aligned themselves with their religious and political beliefs. For example, Protestant territories such as Sweden and the Netherlands emerged with a stronger sense of identity, while the Holy Roman Empire weakened as a result of the war.