During the 1790s he published five string trios and the Opus 8 Serenade before abandoning the genre in favor of other combinations -  notably including the string quartet, and sonatas for piano and one other instrument. His first trio, known as Opus 3, takes as its model Mozart’s Divertimento K. 563 – both consist of six movements, and are composed in the key of E-flat – but even in his earliest works Beethoven is no imitator, but imbues each work with his unique creative spirit.

Here is the Opus 3 with full score, performed by the Grumiaux Trio. https://youtu.be/wtbIT8ALNEA