This site introduces unknown Emanuel Bach (C. P. E. Bach).
ChatGPT4o writes as follows (please note that it may not be accurate):
Emanuel Bachʼs Sonata in D Major Wq. 137 (H. 559) is a work that stands out for its wide range of emotions and expressiveness within his keyboard music. This sonata, while influenced by his father Johann Sebastian Bach, establishes its own unique style. From the outset, it unfolds a bright and lively melody that captivates the listener. The middle section presents delicate and introspective passages, offering a vivid contrast. In the final movement, the energetic theme returns, bringing the piece to a close. Emanuel Bachʼs music is significant as a bridge to the Classical period, and this sonata is a prime example. His works are characterized by improvisational elements and bold harmonic progressions, providing audiences with a fresh sense of surprise.