An American Singing Cowboy group, founded in 1933. The Sons of the Pioneers founding members include Leonard Slye (before he became widely known as Roy Rogers) Bob Nolan and Tim Spencer. Membership changed over the years as the Sons continued to record and tour. Popular on the radio and frequent guest stars in the B-Movie westerns of the day (including appearences in 'Rio Grande' directed by John Ford), the Sons of the Pioneers were designated as 'National Treasures' by the Smithsonian in 1977