Since the 19th century, La Scala Theater Orchestra has played important roles outside its main function of accompanying operas at the city's La Scala Opera House. In the 20th and 21st centuries, the orchestra has been led at one time or another by most of Italy's most prestigious conductors. La Scala Theater Orchestra (Italian: Orchestra del Teatro alla Scala) was recognized for its exceptional quality as it performed at the world premiere of operas by Rossini and Verdi in the 19th century, originally with the first violinist, or, in the very early years, the harpsichordist, as the leader. The orchestra's first conductor was Alberto Mazzucato, who ascended the podium in 1854. His successor Franco Faccio instituted independent concerts in 1872, and the orchestra appeared in Paris during the Exposition Universelle in 1878, one of the first major world's fairs. That triumph led to the establishment of a Società Orchestrale della Scala, which put the group on a firmer institutional footing. Offering two concert seasons annually, the orchestra stimulated the growth of instrumental music in Italy, formerly heavily dominated by opera. The orchestra became self-governing in 1920, under the name Ente Autonomo del Teatro alla Scala. It engaged Arturo Toscanini as its conductor in 1920; he took the group on tour internationally, enlarged it to 100 members (it now boasts 135), and greatly raised its profile in the larger musical world. Toscanini remained music director until 1929 and was followed by some of the top conductors of the 20th and 21st centuries, including Victor de Sabata, Carlo Maria Giulini (principal conductor from 1954 to 1956, with many later appearances and recordings), Claudio Abbado (who led a reorganization that officially named the group the Philharmonic Orchestra of La Scala), Riccardo Muti (1987-2006), Daniel Barenboim, and, as of the early 2020s, Riccardo Chailly. The roster of guest conductors who have appeared over the years reads like a list of legends, including Herbert von Karajan, Leonard Bernstein, and Valery Gergiev. The orchestra's recording catalog stretches back into the 78 rpm era (digital reissues of some of its recordings under Toscanini are available on the RCA label) and includes some of the most famous opera recordings of all time. Under Barenboim, the orchestra recorded Verdi's Requiem for Decca in 2013 and has issued several other recordings of non-operatic works, including an album of Respighi's orchestral music under Chailly in 2020.