Which composer worked closely with both Joseph Sonnleithner and Luigi Cherubini both in personal and professional capacities?
Joseph Sonnleithner: Joseph Ferdinand Sonnleithner (3 March 1766 – 25 December 1835) was an Austrian librettist, theater director archivist and lawyer. 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. Luigi Cherubini: Luigi Cherubini (] ; 8 or 14 September 1760 – 15 March 1842) was an Italian composer who spent most of his working life in France. Luigi Cherubini:  His most significant compositions are operas and sacred music.
Ludwig van Beethoven