Einstein was a dedicated violinist. He even named his beloved instrument Lina.
As put by author Peregrine White:
Einstein relished Mozart, noting to a friend that it was as if the great Wolfgang Amadeus did not “create” his beautifully clear music at all, but simply discovered it already made. This perspective parallels, remarkably, Einstein’s views on the ultimate simplicity of nature and its explanation and statement via essentially simple mathematical expressions.