From the Lyric Opera of Chicago website:
Of all opera composers, none glorified the human voice more than Bellini. His final opera was I Puritani, in which a soprano, tenor, baritone, and bass can truly revel in some of the most thrilling vocal music ever written. Opera companies produce this work only when they can cast fabulous singers with masterful techniques and superb style. Bellini places them within a sweeping historical drama in 17th-century England, in which a passionate young couple find themselves caught up in a conflict between opposing political factions.