Claudio Abbado, Cavaliere di Gran Croce OMRI (Italian pronunciation: [ˈklaudjo abˈbaːdo]; 26 June 1933 – 20 January 2014) was an Italian conductor. One of the most celebrated and respected conductors of the 20th century, particularly in the music of Gustav Mahler, he served as music director of the La Scala opera house in Milan, principal conductor of the London Symphony Orchestra, principal guest conductor of the Chicago Symphony Orchestra, music director of the Vienna State Opera, and principal conductor of the Berlin Philharmonic orchestra.