The Trio Sonata No. 1 in C Major, Op. 4 by Arcangelo Corelli is primarily known for being the opening work of his final set of published trio sonatas, marking the peak of his "chamber" style.While individual sonatas in this set are often praised for their collective influence, No. 1 specifically stands out for its structural elegance, its equalized role of the two top treble instruments and its role in standardizing the sonata da camera (chamber sonata) format.