Complex sentence: However, Emperor Ferdinand was against the plan because the destructive effect it would have of the power balance in Germany, were Saxony, being strongly allied with Denmark, opposed Christina's claims, and neither did she manage to acquire the support of Philip of Spain.
Split into simpler sentences: However, Emperor Ferdinand was against the plan because the destructive effect it would have of the power balance in Germany, where Saxony, being strongly allied with Denmark, opposed Christina's claims. Nor did she manage to acquire the support of Philip of Spain.