His first success was Il pirata in 1827 , followed by I Capuleti e Montecchi in 1830 . Then came his most famous operas La sonnambula ( 1831 ) , Norma ( 1831 ) and his last I puritani ( 1835 ) , which proved a sensational triumph . His greatest works are I Capuleti ed i Montecchi ( 1830 ) , La sonnambula ( 1831 ) , Norma ( 1831 ) , Beatrice di Tenda ( 1833 ) , and I puritani ( 1835 ) .