In addition to Mendelssohn, he attracted the attention of Rossini who assisted him to launch his first opera, "Romilda" (which was a failure), at Milan. Mendelssohn obtained for Hiller an entrée to the Gewandhaus, and afforded an opportunity for the public presentation of Hiller's oratorio "Die Zerstörung Jerusalems" (The Destruction of Jerusalem, 1840). After a year of study in Church music at Rome, Hiller returned to Leipzig, and during the season of 1843–44 conducted the Gewandhaus concerts. By this time his position in the musical world was established, and honors and appointments were showered upon him. In 1845 Robert Schumann dedicated to Hiller his piano concerto. Hiller became municipal kapellmeister of Düsseldorf in 1847, and in 1850 received a similar appointment at Cologne, where he founded Cologne Conservatoire that year and remained as Kapellmeister until 1884. During this time, he was twelve times festival director of the Lower Rhenish Music Festival, and conducted the Gürzenich concerts. He worked in Dresden as well. Thus he played a leading part in Germany's musical life. And he was conductor at the Italian Opera in Paris during the season of 1852–53.