Complex sentence: Furthermore, as the uncle of Theophilos's new wife, the Empress Theodora, his position at court was now unassailable, as shown by the fact that the Emperor later served as godfather for Manuel's children.
Split into simpler sentences: Furthermore, as the uncle of Theophilos's new wife, the Empress Theodora, his position at court was now unassailable. It is indicative that the Emperor later served as godfather for Manuel's children.