When the state celebrated its 100th birthday in 1947, one of the principal events was an original musical telling the story of the Mormon migration across the plains to Utah.Titled "Promised Valley," it was the result of collaboration between Crawford Gates, who wrote the music, and Arnold Sundgaard, a successful Broadway author.The choice of Gates to compose the music was a surprise to many who had expected a more experienced and better-known musician would get the job. Gates was 25 years old, had served as a Navy officer in World War II and was studying for his master's degree in music at Brigham Young University."I know lots of people had their fingers crossed, but I knew I could do the job," Gates says.After all, when he was 17, he had directed the San Jose California Symphony in playing a symphony he composed. At its conclusion, the audience and orchestra gave him a standing ovation.Now 86, Gates and his wife, Georgianna, live in their home near the mouth of Parleys Canyon in Salt Lake City, where they have a sweeping view of the Salt Lake Valley. He looks back at a successful career that includes being chairman of the BYU music department and conductor of symphony orchestras in Beloit, Wis., and Quincy, Ill., and Rockford, Ill. He and Maurice Abravenel, the late, well-known conductor of the Utah Symphony, were close friends, and Gates was a frequent guest conductor at Utah Symphony concerts.A look at the numbers is proof of the overwhelming success "Promised Valley" has enjoyed since it was written 60 years ago.It was translated into six languages for performances by church groups in other countries. A shortened version aimed at tourists played for 19 summers in downtown Salt Lake City with the lighted spires of the Salt Lake Temple in the background.There were also many full-fledged revivals in the Promised Valley Playhouse on State Street.The original "Promised Valley" played for almost a month before large and enthusiastic audiences in the University of Utah Stadium, where 10,000 seats had been added to form a bowl at the north end around a large stage with the latest and best sound and lighting equipment available at the time.Alfred Drake, who had been singing and starring on Broadway for four years in "Oklahoma," was signed as the lead in "Promised Valley," along with Jet McDonald and a strong cast of local actors in supporting roles. Lowell Lees directed the show, with Abravanel directing the music.The success of "Promised Valley" was also a shared effort between the state's Centennial Commission and the University of Utah.