The banjo has its origins in Africa with a distant musical relative known as the mbanza. Merely a hollowed gourd covered with a stretched skin and string, the mbanza would later become the banjo. The banjo was introduced in the Caribbean by the colonial slave trade in the late 1600s. Within a century, the use of the banjo was widespread. At the turn of the the 20th century, the banjo player arguably saw the height of his popularity as a mainstream entertainment. Banjo playing styles have since branched and defined themselves.
One of the two main types of banjo, the five-string banjo is the most common style of this instrument today. Although the five-string banjo does indeed have five strings, the fifth additional string is actually shorter than the other four. This fifth string is tuned at the highest pitch but is not often fretted. Instead, this string serves as a drone string that is played to harmonic effect with the rest of the musical piece. Variations of the five-string banjo include the pony and piccolo banjo.
The four-string banjo is separated into two primary models: the tenor banjo and the plectrum banjo. The tenor banjo has a shorter neck than its five-string sibling, with higher tuning suited to a strumming style. Tenor banjos are often added to jazz bands. The plectrum banjo is nearly identical to the typical five-string banjo, sans the smaller fifth string. A plectrum is another term for a pick used to play string instruments. Therefore, the plectrum banjo is plucked with a pick more often than it is with fingers.
Despite the popular imagery of banjos and bluegrass, the different styles of banjos has led to a wide variety of playing styles and genres. Although the five-string banjo is commonly used in bluegrass, it has been used in modern jazz and rock as well. Celtic music is sometimes played on a three-finger-style with a five-string banjo but is more commonly performed with four-string banjos.