Question: Which composer worked closely with both Joseph Sonnleithner and Luigi Cherubini both in personal and professional capacities?
Sentence (from "Joseph Sonnleithner"): He was a personal friend and attorney of Ludwig van Beethoven, and he wrote numerous librettos, among them, Beethoven's stage opera "Fidelio", "Faniska" by Luigi Cherubini and "Agnes Sorel" by Adalbert Gyrowetz.
Relevant evidence: Yes