What are two problems that compicated the search for peace and stability in Europe after war ended?

Two problems that complicated the search for peace and stability in Europe after the end of the Thirty Year's War (1618-1648) were:

1. Shifting political alliances: The war had led to significant changes in the European power dynamics. Alliances had shifted and there was a fear of resurgence of conflict between the major powers, particularly France, Sweden, and the Habsburg Monarchy (which included Spain and the Holy Roman Empire).

2. Religious divisions: The war had been partly fueled by religious tensions between Protestant and Catholic states. While the Peace of Westphalia had established the principle of cuius regio, eius religio (the religion of the ruler determines the religion of the state), religious conflicts persisted and continued to complicate efforts to build lasting peace.