Upon his return to Germany, he worked primarily as a landscape painter. Shortly thereafter, he was diagnosed with tuberculosis. As his illness worsened, he went back to Italy in hopes that the climate would be more amenable, and settled in Olevano in 1822.[1] His disease worsened, however and, after much suffering, he died there. He was buried in the local cemetery.
In 1998/99, to celebrate Horny's 200th birthday, the Hamburger Kunsthalle, in cooperation with the Kunstsammlungen zu Weimar, presented "Ein Romantiker im Lichte Italiens", the first full exhibition devoted to Horny's work.[2]