Prior to Beethoven, trios were linked to Baroque tradition, and each instrument was locked in its place. After him, the cello was emancipated, the piano became an orchestra in itself, and the three instruments began to engage in uninhibited dialogue. Schumann latched onto this and had Beethoven in mind when he composed, making the instruments sing while recovering the severity involved in counterpoint.
Robert SchumannTrio in fa maggiore op. 80Ludwig van BeethovenTrio in mi bemolle maggiore op. 70 n. 2