Old Mountain Dew · In the Blue Hills of Virginia

Alton and Rabon Delmore were close-harmony singers from north Alabama whose soft, swinging brother duets bridged the world of old-time music and the rhythm-driven sound to come. They joined the Grand Ole Opry in 1933 and became one of its most popular early acts, and through the 1930s they recorded steadily for Columbia and then for Victor's Bluebird label — sides like "Brown's Ferry Blues" that married country singing to a loose, bluesy guitar lilt.

Their most influential records, though, came after the war, when the brothers signed with Syd Nathan's King Records in Cincinnati. The King singles of the late 1940s pushed their sound toward what would soon be called rockabilly: a boogie beat, harmonica and electric guitar, an easy rhythmic roll. "Blues Stay Away From Me," cut for King in 1949, became their biggest hit and one of the most-covered songs of the era.

The Delmores' importance to bluegrass is partly repertoire and partly blood harmony. Their catalog of brother-duet numbers became standard material for the close-harmony acts that followed, and their effortless two-part singing set a benchmark that the Monroes, the Stanleys, the Louvins, and every other brother act measured themselves against.

Rabon Delmore died young, in 1952, ending one of the longest and most productive partnerships in country music. By then the brothers had recorded several hundred sides across two decades — a body of singles that fed directly into bluegrass, honky-tonk, and rock and roll alike.

Session details drawn in part from the Bluegrass Discography.