The german composer Heinrich Dorn (1804 – 1892) was born in Königsberg, and studied in Leipzig and Berlin. He was a very sought-after conductor and wrote many operas. One of them was called “Die Nibelungen”, was premiered in 1854, conducted by Franz Liszt, and was a huge success. (Wagner started on his “little Nibelungen project” in 1853 and finished many years later.)
The two composers had been colleagues at the opera house in Riga in the 1830′s, and might even have known each other from their early days in Leipzig. But they didn’t seem to get along. The classicist Dorn worked as a critic as well, and therefore is known to the afterworld through the eyes of Richard Wagner’s scorn over having his music be critizised as “lacking lively plot, singable melodies and at least recognisable forms”.