Beollmann, Gliere, Juon, Rachmaninoff, Saint-Saens & Woelfl:

When Ludwig van Beethoven wrote his first two sonatas for piano and violoncello (op. 5) in 1796, he was entering new compositional territory. Violin sonatas already existed; Mozart had already written several, but the cello had not yet established itself as a solo instrument equal to the violin in chamber music. (Hanssler Classic)