Little is known about the exact origin of the music now known as the blues. No specific year can be cited as the origin of the blues, largely because the style evolved over a long period and existed in approaching its modern form before the term blues was introduced and before the style was thoroughly documented. Ethnomusicologist Gerhard Kubik traces the roots of many of the elements that were to develop into the blues back to the African continent, the "cradle of the blues". One important early mention of something closely resembling the blues comes from 1901, when an archaeologist in Mississippi described the songs of black workers which had lyrical themes and technical elements in common with the blues.
There are few characteristics common to all blues, as the genre takes its shape from the peculiarities of each individual performance. Some characteristics, however, were present prior to the creation of the modern blues, and are common to most styles of African American music. The earliest blues-like music was a "functional expression, rendered in a call-and-response style without accompaniment or harmony and unbounded by the formality of any particular musical structure". This pre-blues music was adapted from the field shouts and hollers performed during slave times, expanded into "simple solo songs laden with emotional content".
Many of these blues elements, such as the call-and-response format, can be traced back to the music of Africa. The use of melisma and a wavy, nasal intonation also suggests a connection between the music of West and Central Africa and the blues. The belief that blues is historically derived from the West African music including from Mali is reflected in Martin Scorsese's often quoted characterization of Ali Farka Touré's tradition as constituting "the DNA of the blues".
Perhaps the most compelling African instrument that is a predecessor to an African-American instrument is the "Akonting", a folk lute of the Jola tribe of Senegambia. It is a clear predecessor to the American banjo in its playing style, the construction of the instrument itself and in its social role as a folk instrument. The Kora is played by a professional caste of praise singers for the rich and aristocracy (called griots or jalis) and is not considered folk music. Jola music may not have been influenced much by North African/Middle Eastern music, which may point to African American music not being, according to Sam Charters, related to kora music. The music of the Akonting and that played by on the banjo by elder African-American banjo players, even into the mid 20th century is easily identified as being very similar. The akonting is perhaps the most important and concrete link that exists between African and African-American music.
The historian Sylviane Diouf and ethnomusicologist Gerhard Kubik identify Islamic music as an influence on blues music. Diouf notes a striking resemblance between the Islamic call to prayer (originating from Bilal ibn Rabah, a famous Abyssinian African Muslim in the early 7th century) and 19th-century field holler music, noting that both have similar lyrics praising God, melody, note changes, "words that seem to quiver and shake" in the vocal chords, dramatic changes in musical scales, and nasal intonation. She attributes the origins of field holler music to African Muslim slaves who accounted for an estimated 30% of African slaves in America. According to Kubik, "the vocal style of many blues singers using melisma, wavy intonation, and so forth is a heritage of that large region of West Africa that had been in contact with the Arabic-Islamic world of the Maghreb since the seventh and eighth centuries." Kubik also notes that stringed instruments (including ancestors of the banjo) were generally favored by Muslim African slaves, while drumming was generally favored by non-Muslim African slaves.
While the findings of Kubik and others clearly attest to the essential Africanness of many essential aspects of blues expression, studies by Willie Ruff and others have situated the origin of "black" spiritual music inside enslaved peoples' exposure to their masters' Hebridean-originated gospels. African-American economist and historian Thomas Sowell also notes that the southern, black, ex-slave population was acculturated to a considerable degree by and among their Scots-Irish "redneck" neighbours. Additionally, there are theories that the four-beats-per-measure structure of the blues might share its origins with the Native American tradition of pow wow drumming.
Field holler music, also known as Levee Camp Holler music, was an early form of African American music, described in the 19th century. Field hollers laid the foundations for the blues, spirituals, and eventually rhythm and blues. Field hollers, cries and hollers of the slaves and later sharecroppers working in cotton fields, prison chain gangs, railway gangs (Gandy dancers) or turpentine camps were the precursor to the call and response of African American spirituals and gospel music, to jug bands, minstrel shows, stride piano, and ultimately to the blues, rhythm and blues, jazz and African American music in general.Sylviane Diouf and Gerhard Kubik have traced the origins of field hollers to African Muslim slaves, who were influenced by the Islamic musical tradition of West Africa (see African roots above).
The most important American antecedent of the blues was the spiritual, a form of religious song with its roots in the camp meetings of the Great Awakening of the early 19th century. Spirituals were a passionate song form, that "convey(ed) to listeners the same feeling of rootlessness and misery" as the blues. Spirituals, however, were less specifically concerning the performer, instead about the general loneliness of humankind, and were more figurative than direct in their lyrics. Despite these differences, the two forms are similar enough that they can not be easily separated -- many spirituals would probably have been called blues had that word been in wide use at the time.
The social and economic reasons for the appearance of the blues are not fully known. Blues has evolved from an unaccompanied vocal music of poor black laborers into a wide variety of styles and subgenres, with regional variations across the United States. African American work songs were an important precursor to the modern blues; these included the songs sung by laborers like stevedores and roustabouts, and the field hollers and "shouts" of slaves. The first appearance of the blues is not well defined and is often dated between 1870 and 1900, a period that coincides with the emancipation of the slaves and the transition from slavery to sharecropping and small-scale agricultural production in the southern United States.
Several scholars characterize the early 1900s development of blues music as a move from group performances to a more individualized style. They argue that the development of the blues is associated with the newly acquired freedom of the slaves. According to Lawrence Levine, "there was a direct relationship between the national ideological emphasis upon the individual, the popularity of Booker T. Washington's teachings, and the rise of the blues." Levine states that "psychologically, socially, and economically, Negroes were being acculturated in a way that would have been impossible during slavery, and it is hardly surprising that their secular music reflected this as much as their religious music did."
An important reason for the lack of certain knowledge about the origins of the blues is the earliest blues musicians' tendency to wander through communities, leaving little or no record of precisely what sort of music they played or where it came from. Blues was generally regarded as lower-class music, unfit for documentation, study or enjoyment by the upper- and middle-classes
Blue notes pre-date their use in blues. English composer Samuel Coleridge-Taylor's "A Negro Love Song", from his The African Suite for Piano composed in 1898, contains blue third and seventh notes.
African American composer W. C. Handy wrote in his autobiography of the experience of sleeping on a train traveling through (or stopping at the station of) Tutwiler, Mississippi around 1903, and being awakened by:
... a lean, loose-jointed Negro who had commenced plucking a guitar beside me while I slept. His clothes were rags; his feet peeped out of his shoes. His face had on it some of the sadness of the ages. As he played, he pressed a knife on the strings in a manner popularized by Hawaiian guitarists who used steel bars. ... The effect was unforgettable. His song, too, struck me instantly... The singer repeated the line ("Going' where the Southern cross' the Dog") three times, accompanying himself on the guitar with the weirdest music I had ever heard.
Handy had mixed feelings about this music, which he regarded as rather primitive and monotonous, but he used the "Southern cross' the Dog" line in his 1914 "Yellow Dog Rag", which he retitled "Yellow Dog Blues" after the term blues became popular. "Yellow Dog" was the nickname of the Yazoo and Mississippi Valley Railroad.
Blues later adopted elements from the "Ethiopian (here, meaning "black") airs" of minstrel shows and Negro spirituals, including instrumental and harmonic accompaniment. The style also was closely related to ragtime, which developed at about the same time, though the blues better preserved "the original melodic patterns of African music".
Since the 1890s, the American sheet music publishing industry had produced a great deal of ragtime music. The first published ragtime song to include a 12-bar section was "One o' Them Things!" in 1904. Written by James Chapman and Leroy Smith, it was published in St. Louis, Missouri, by Jos. Plachet and Son. Another early rag/blues mix was "I Got the Blues" published in 1908 by Antonio Maggio of New Orleans 
In a long interview conducted by Alan Lomax in 1938, Jelly Roll Morton recalled that the first blues he had heard, probably around 1900, was played by a singer and prostitute, Mamie Desdunes, in Garden District, New Orleans. Morton sang the blues: "Can't give me a dollar, give me a lousy dime/ You can't give me a dollar, give me a lousy dime/ Just to feed that hungry man of mine". The interview was released as The Complete Library of Congress Recordings.
In 1912 the sheet music industry published another blues composition--"Dallas Blues" by Hart A. Wand of Oklahoma City, Oklahoma. Two other blues-like compositions, precipitating the Tin Pan Alley adoption of blues elements, were also published in 1912: "Baby Seals' Blues" by Baby Franklin Seals (arranged by Artie Matthews) and "Memphis Blues", another ragtime arrangement with a single 12-bar section, by W. C. Handy. Also in 1912 (on November 9), another song, "The Blues", was copyrighted by LeRoy "Lasses" White, but not actually published until 1913.
Handy was a formally trained musician, composer and arranger who helped to popularize the blues by transcribing and orchestrating blues in an almost symphonic style, with bands and singers. He became a popular and prolific composer, and billed himself as the "Father of the Blues"; however, his compositions can be described as a fusion of blues with ragtime and jazz, a merger facilitated using the Afro-Cuban habanera rhythm that had long been a part of ragtime; Handy's signature work was the St. Louis Blues.
Songs from this period had many different structures. A testimony of those times can be found for instance in Henry Thomas's recordings. However, the twelve-, eight-bar, or sixteen-bar structure based on tonic, subdominant and dominant chords became the most common. Melodically, blues music is marked by the use of the lowered third and dominant seventh (so-called blue notes) of the associated major scale. The standard 12-bar blues form is noted in uncorroborated oral histories as appearing communities throughout the region along the lower Mississippi River during the decade of the 1900s (and performed in New Orleans at least since 1908). One of these early sites of blues evolution was along Beale Street in Memphis, Tennessee. However, author Eileen Southern has pointed out several contrasting statements by old-time musicians. She cites Eubie Blake as saying "Blues in Baltimore? Why, Baltimore is the blues!" and Bunk Johnson as claiming that the blues was around in his childhood, in the 1880s.
One of the first professional blues singers was Ma Rainey, who claimed to have coined the term blues. Classic female urban or vaudeville blues singers were popular in the 1920s, among them Mamie Smith, Gertrude Ma Rainey, Bessie Smith, and Victoria Spivey. Mamie Smith, more a vaudeville performer than a blues artist, was the first African- American to record a blues in 1920; her "Crazy Blues" sold over 75,000 copies in its first month.
The musical forms and styles that are now considered the "blues" as well as modern "country music" arose in the same regions during the nineteenth century in the southern United States. Recorded blues and country can be found from as far back as the 1920s, when the popular record industry developed and created marketing categories called "race music" and "hillbilly music" to sell music by blacks for blacks and by whites for whites respectively. At the time, there was no clear musical division between "blues" and "country", except for the race of the performer, and even that sometimes was documented incorrectly by record companies.