The earliest form of music known to man is vocal music. Before 900 A.D., vocal music was not written down. It was sung from person to person, often transmitting vital information about history and culture. In the Middle Ages, vocal music started its evolution into modern form.
During the Middle Ages, chant singing tied to religious practices was the common form of vocal music. Songs were monophonic, containing a single musical line with no harmony. Chants were sung often in religious settings. In secular environments, troubadours, wandering musicians for hire, sang monophonic songs. Much of the surviving troubadour music of this era comes from France and Germany.
With the European Renaissance beginning in the 14th Century, Western vocal music expanded from monotonal chant to increasingly complex song structures and harmonies. Madrigals, popular secular songs of the era, became the purview of both troubadours and amateurs. Singing with instrumental accompaniment rose to prominence.
As harmonies and musical structures evolved in European-influenced countries, so did songs. Vocal music expanded into the theater in the form of the opera, a musical play. Composers also wrote songs to be performed in the concert hall.
Contemporary vocal music in European-influenced countries such as the United States has its roots in the Western tradition, which includes concepts such as musical notation on a five-line staff, an eight-note musical octave and harmonies based on major and minor scales.
Vocal music takes on distinctly different forms in cultures outside of the European tradition. In countries such as India, vocal music can include notes that are nonexistent on the Western eight-note octave. Other countries continue to pass on vocal music, such as folk songs, through the oral tradition instead of written form.