Complex sentence: Notwithstanding Bussy's various delinquencies the cousins had always been friends; and the most amusing and characteristic part of Madame de Sévigné's correspondence, before the date of her daughter's marriage, is addressed to him.
Split into simpler sentences: Notwithstanding Bussy's various delinquencies, the cousins had always been friends. The most amusing and characteristic part of Madame de Sévigné's correspondence before her daughter's marriage, is addressed to him.