Beethoven composed his greatest symphony after going completely deaf

By the time Beethoven completed his Ninth Symphony in 1824 — containing the famous 'Ode to Joy' finale — he had been profoundly deaf for several years. At the premiere, he continued conducting even after the orchestra had stopped. A soloist turned him around to see the audience giving him a standing ovation. He could not hear a single note of it.

Source: Marek, George, 'Beethoven: Biography of a Genius' (1969)