thumb|Leopold Stokowski, music director, 1912–1938 Leopold Stokowski became music director in 1912 and brought the orchestra to national prominence. Under his guidance, the orchestra gained a reputation for virtuosity, and developed what is known as the "Philadelphia Sound." Stokowski left the orchestra in 1941, and did not return as a guest conductor for nearly 20 years.
thumb|Leopold Stokowski, music director, 1912–1938 Leopold Stokowski became music director in 1912 and brought the orchestra to national prominence Under his guidance, the orchestra gained a reputation for virtuosity, and developed what is known as the "Philadelphia Sound." Stokowski left the orchestra in 1941, and did not return as a guest conductor for nearly 20 years.