George Szell developed the Cleveland Orchestra into one of the world’s great performing entities, and remained its chief until his death in 1970. In 1967 he stated: "My aim in developing the Cleveland Orchestra has been to combine the finest virtues of the great European orchestras of pre-World War times with the most distinguished qualities of our leading American orchestras. In other words, we put the American orchestra’s technical perfection, beauty of sound, and adaptability to the styles of various national schools of composers into the service of warm-hearted, spontaneous music-making in the best European tradition". Szell began conducting Haydn symphonies in Prague in 1930, and they were conspicuous in his repertory for the rest of his life