Complex sentence: The Piedmontese legal system entered in force in Sardinia, and the last viceroy, Claudio Gabriele de Launay, left Cagliari on March 4,1848, while the island was divided in three provinces ruled by their prefects, as it had happened in Piedmont in 1815.
Split into simpler sentences: The Piedmontese legal system entered in force in Sardinia, and the last viceroy, Claudio Gabriele de Launay, left Cagliari on 4 March 1848. The island was divided into three provinces ruled by their prefects, as had happened in Piedmont in 1815.