No, Beethoven was not completely deaf when he wrote the Moonlight Sonata. He composed this famous piece in 1801, during the early stages of his hearing loss. At that time, he was experiencing tinnitus and a gradual decline in his hearing, but he could still hear some sounds and music.
Beethoven’s hearing loss progressed over the years, and by the time he composed his later works, he was almost completely deaf. Despite his hearing impairment, Beethoven continued to create some of his most iconic music, including the Moonlight Sonata, which remains one of his most beloved compositions.