Complex sentence: After the marriage between Catherine and Peter, Johanna was dismissed and prohibited the entrance to Russia, it was even prevented to maintain correspondence him with his daughter, although this one managed to send some letters to him of clandestine form.
Split into simpler sentences: After the marriage between Catherine and Peter, Johanna was forced to leave Russia. She was prohibited form entrance to Russia, and even prevented to maintain correspondence with her daughter, although she managed to send some letters to her of clandestine form.