As the principal architects of Southern rock, the Allman Brothers Band forged this new musical offshoot from elements of blues, jazz, soul, R&B and rock and roll. Along with the Grateful Dead and Cream, they help advance rock as a medium for improvisation. Their kind of jamming required a level of technical virtuosity and musical literacy that was relatively new to rock & roll, which had theretofore largely been a song-oriented medium. The original guitarists in the Allman Brothers Band – Duane Allman and Dickey Betts – broke that barrier with soaring, extended solos. Combined with organist Gregg Allman’s gruff, soulful vocals and Hammond B3 organ, plus the forceful, syncopated drive of a rhythm section that included two drummers, the Allman Brothers Band were a blues-rocking powerhouse from their beginnings in 1969.