The banjo entered the era of Minstrelsy - 'blacked up' performers playing like the black Africans they had seen and learnt from. This seems to have happened from about 1820 onwards. The most well known was Joel Sweeney who with his 'Minstrels' was already popular by the 1830s. Sweeney is often credited with introducing the 5th string - albeit an additional long string now called the 4th (since the short string was already present)The gourd banjos were rough and ready - made from locally obtainable materials and not particularly reliable in tuning or tone. The white performers started to regularise the components by manufacture - from craftsmen at first and then by factory as the popularity of banjos increased. Sweeney used a drum manufacturer called William Boucher from Baltimore to make his banjos. Boucher was probably the first to sell to the public
In 1860 Lincoln was elected president of the United States and his election threatened the economy of the South. The North had given up slavery some time earlier, but the South was based on a slave culture. South Carolina seceded from the Union and started a war. Eleven states left the union and the war raged from 1861 to 1865. At the end of it, slavery had formally been abolished. For whatever reason, the popularity of the banjo took off after the war.
The first banjos were 5-string and played clawhammer style. Innovations such as frets, steel strings, the resonator, the first tone ring and the fingerpicking style developed in the 1870s - 1880s. Henry C Dobson is often credited with the introduction of these innovations. His instruments were made by J H Buckbee of New York.
Now that manufacturing was establishing, a variety of banjo types started to emerge - principally 4 string tenor and plectrum banjos. The first Tenor Banjo is credited to Professor Stepner (designer) and J.B.Schall of Chicago (manufacturer) at the turn of the century. It was called at this time a 'Banjorine'. The banjo remained popular until the 1920s - 1930s when the guitar started to replace it as the popular instrument. It remained in small pockets such as Appalachia, re-emerging with the rise of Bluegrass in the 1950s.