Soul-Jazz, which was the most popular jazz style of the 1960s, differs from bebop and hard bop (from which it originally developed) in that the emphasis is on the rhythmic groove. Although soloists follow the chords as in bop, the basslines (often played by an organist if not a string bassist) dance rather than stick strictly to a four-to-the bar walking pattern. The musicians build their accompaniment around the bassline and, although there are often strong melodies, it is the catchiness of the groove and the amount of heat generated by the soloists that determine whether the performance is successful. Soul-jazz's roots trace back to pianist Horace Silver, whose funky style infused bop with the influence of church and gospel music, along with the blues. Other pianists who followed and used similar approaches were Bobby Timmons, Junior Mance, Les McCann, Gene Harris (with his Three Sounds), and Ramsey Lewis. With the emergence of organist Jimmy Smith in 1956 (who has dominated his instrument ever since), soul-jazz organ combos (usually also including a tenor, guitarist, drummer, and an occasional bassist) caught on, and soulful players became stars, including Brother Jack McDuff, Shirley Scott, Jimmy McGriff, Charles Earland, and Richard "Groove" Holmes, along with such other musicians as guitarists Grant Green, George Benson and Kenny Burrell; tenors Stanley Turrentine, Willis "Gator" Jackson, Eddie "Lockjaw" Davis, David "Fathead" Newman, Gene "Jug" Ammons, Houston Person, Jimmy Forrest, King Curtis, Red Holloway, and Eddie Harris; and altoist Hank Crawford. Despite its eclipse by fusion and synthesizers in the 1970s, soul-jazz has stayed alive and made a healthy comeback in recent years.