Fibromyalgia syndrome (FMS) is now a recognized clinical entity causing chronic and disabling pain. For several centuries, muscle pains have been known as rheumatism and then as muscular rheumatism. The term fibrositis was coined by Gowers in 1904 and was not changed to fibromyalgia until 1976. Smythe laid the foundation of modern FMS in 1972 by describing widespread pain and tender points. The first sleep electroencephalogram study was performed in 1975. The first controlled clinical study with validation of known symptoms and tender points was published in 1981. This same study also proposed the first data-based criteria. The important concept that FMS and other similar conditions are interconnected was proposed in 1984. The first American College of Rheumatology criteria were published in 1990 and neurohormonal mechanisms with central sensitization were developed in the 1990s. Serotonergic/norepinephric drugs were first shown to be effective in 1986.