Gratitude is an organic response to royal support.  Composers like Mozart, Haydn, and Eybler showed their thankfulness by writing with a sense of childlike playfulness and humor, delighting audiences over 200 years later. 

Mozart: String Quartet in B flat Major, K. 589
Haydn: String Quartet in C Major, Op. 37
Eybler: String Quartet in E flat major, Op. 10 no 1