Complex sentence: Wallenstein's letters refuting the accusations against him remained unanswered, after realizing that the emperor was positioning troops in such a manner as to surround him he decided to flee to the Swedes.
Split into simpler sentences: Wallenstein's letters refuting the accusations against him remained unanswered. After realizing that the emperor was positioning troops in such a manner as to surround him he decided to flee to the Swedes.