Complex sentence: William had no sons, nor had his only Protestant kinsman, Duke Nicholas (1833--1903); consequently power was scheduled to pass to a Roman Catholic branch of the family, raising difficulties about the relations between church and state.
Split into simpler sentences: William had no sons, nor had his only Protestant kinsman, Duke Nicholas (1833--1903). Consequently, power was due to pass to a Roman Catholic branch of the family, raising difficulties concerning the relations between church and state.