Before Buddy Holly, before the Rolling Stones, Bruce Springsteen and a million unknown garage bands, there was Bo Diddley -- and the beat that bears his name.

A Rock and Roll Hall of Famer and one of the genre's undisputed icons, Diddley helped cast the sonic template of rock more than 50 years ago with a signature syncopated rhythm -- chunk-a-chunk-chuck, a-chunk-chunk -- that became recognized as "the Bo Diddley beat."

Diddley, who often referred to himself as "the Originator" to emphasize his contribution to rock music, died Monday. He was 79.

He had long battled hypertension and diabetes, among other health problems, and was hospitalized for 11 days after suffering a stroke onstage in Iowa in May 2007. In August, he complained of dizziness and nausea during a routine medical checkup and was hospitalized with a heart attack.

Diddley is recognized as one of rock's most influential guitarists, expanding the instrument's vocabulary with a crunching, tremolo-laden sound. He played a rectangular "cigar box" guitar of his own design, an instantly recognizable visual counterpart to the distinctive rhythm that bore his name and provided the backbeat for his own songs, including Bo Diddley, Mona and Who Do You Love.

"Bo's one of the guys who invented rock 'n' roll," said Eric Burdon, lead singer of the Animals. "He took two cultures . . . country and western and the kind of blues that used to be known as 'race music' -- and put them together."

Diddley is considered by some a pioneer of rap with his 1959 Top 20 hit Say Man. On that track, Diddley and his maraca player, Jerome Green, trade jive-talking insults over a percolating beat. He also has been cited as a progenitor of hard rock and heavy metal music for his distortion-drenched sound and near-brutal manner of attacking the fret board.

"He was a wonderful, original musician who was an enormous force in music and was a big influence on the Rolling Stones," said the group's lead singer, Mick Jagger. "He was very generous to us in our early years and we learned a lot from him."

Diddley was born Otha Ellas Bates in McComb, Miss. His father died shortly after his birth and his 16-year-old mother was unable to support him. Diddley was later adopted by his mother's cousin, Gussie McDaniel. She changed his name to Ellas McDaniel and brought him to Chicago.

There, he began studying violin at age seven and taught himself to play guitar in the early 1940s.

In school, the rambunctious Ellas acquired his nickname. By most accounts, neighbourhood kids started calling him "bow diddley" -- slang for "bully." The name also recalled the diddley bow, however, an African single-string guitar seminal to blues music.

He dropped out of school at 15, playing his guitar on the street for change.

In 1954, he was a fixture on the local music circuit when he cut a two-song demo of his songs Uncle John and I'm a Man, basing his recordings on the exultant, frenetic music he had been heard in the Pentecostal church as a child.

In 1955, the demo landed him a deal with Chicago's Chess Records, home to Willie Dixon, Howlin' Wolf and Chuck Berry. The title for Uncle John was changed to Bo Diddley. When the single was released, the song shot to No. 1 on the national R&B; chart.

Diddley's panache and swaggering stage presence influenced musicians on both sides of the Atlantic, among them Jagger, James Brown and Jimi Hendrix. Diddley's early use of amplified electric-guitar effects -- including reverb, echo and distortion -- also played an important part in the evolution of the sound of rock music when they were taken to further extremes by Hendrix, the Doors and others.

Even though Diddley helped establish rock 'n' roll's rhythmic bedrock, he never enjoyed the financial success or critical recognition of his two chief contemporaries, Berry and Little Richard. "Diddley remained firmly rooted in the ghetto," author George R. White wrote in his biography Bo Diddley: Living Legend. "Both his music and his image were too loud, too raunchy, too black to ever cross over."

Diddley is survived by four children, 15 grandchildren, 15 great-grandchildren, three great-great-grandchildren and a brother.