Complex sentence: Little is known of Henry's personal life, except that he was apparently rich enough to marry the Earl of Roscommon's daughter; much of his money was probably inherited from his grandfather, who made a fortune at the Irish Bar.
Split into simpler sentences: Little is known of Henry's personal life, except that he was apparently rich enough to marry the Earl of Roscommon's daughter. THe money was probably inherited from his grandfather, who made a fortune at the Irish Bar.