Complex sentence: He fought in the constitutionalist army against the Austrians at Rieti (March 7,1821), and on the re-establishment of autocracy he was arrested and imprisoned for three months by order of the prince of Canosa, the chief of police, his particular enemy.
Split into simpler sentences: He fought in the constitutionalist army against the Austrians at Rieti (March 7,1821). On the re-establishment of autocracy, he was arrested and imprisoned for three months by order of the Prince of Canosa, the chief of police and his particular enemy.