Complex sentence: The Princes of Canino and Musignano formed the genealogically senior line of the Bonaparte family following the death of Joseph Bonaparte in 1844, founded by one of Emperor Napoleon I's younger brothers, Lucien Bonaparte.
Split into simpler sentences: The Princes of Canino and Musignano formed the genealogically senior line of the Bonaparte family following the death of Joseph Bonaparte in 1844. The line was founded by one of Emperor Napoleon's younger brothers, Lucien Bonaparte.