Karl Ferdinand Heckel (1800-1870) founded a shop for musical instruments in Mannheim in 1821. Soon afterwards, he added a music publishing branch to his firm. In 1823 he acquired the music publishing company G. Kreitner from nearby Worms. In 1857, his son Emil Heckel (1831-1908) became partner of the company.
After Karl Ferdinand Heckels death in 1870, his two sons Emil and Karl (1858-1923) led the firm together under the original name (K.F. Heckel), but Karl left the company soon afterwards to pursue other projects. Emil Heckel was a talented activist in the 1870s, playing a leading role in the building of Wagner's festival theater in Bayreuth. He has been described as follows: „Heckel war, heute würde man sagen: ein begnadeter Netzwerker und überaus begabter Kaufmann“ (in today's terms, a gifted networker and exceptional businessman).
Karl Heckel jnr. shared these qualities. His moment came in the most significant period of the firm's history, which was much later, at the end of the 19th century. Strangely, although Mannheim was a backwater compared with Vienna, where Brahms, Wolf and R. Strauss had raised the Lied to great heights in the previous 30 years, Heckel made a great contribution to the publication of this genre. This is because of the pure chance that there was a group of Wolf supporters in Mannheim, set up by Oskar Grohe, a judge by profession, who had been inspired by a laudatory article on Wolf by Joseph Schalk in the Münchene Algemeine Zeitung in 1890, which according to Walker, Wolf's biographer, "kindled a flame of enthusiasm throughout South Germany". This circle, which included the opera conductor Felix Weingartner and Karl Heckel, promoted the premiere of Wolf's opera Der Corregidor at Mannheim in 1896, after it had been rejected by the major opera houses in Austria-Hungary.
As part of this Wolf vogue, in 1895 the firm purchased all compositions by Hugo Wolf (1860-1903) from B. Schott's Söhne in Mainz. Subsequently Emil Heckel edited Wolf's complete songs, and the firm also reprinted earlier editions by Schott, Emil Wetzler and C. Lacom. In addition, 1902 and 1903 saw the publication of six orchestrated editions of Hugo Wolf songs. After Emil Heckel's death in 1908, the Goethe-Songs, the Mörike-Songs as well as the Italian Songbook of Wolf passed to C.F. Peters in Leipzig, and Heckel's moment in the limelight of publishing history had passed.
Examples for the stucture of Heckel's plate numbering: