Harps are played throughout much of the world; in Africa alone, there are more than 150 distinct harp traditions. Francis Galpin suggests that the harp's ancestor was a hunting bow, but the history of this complex instrument is far from clear. We know through epic tales, poetry and works of art that harps have existed since at least 4000 in Babylonia and Mesopotamia. They have been represented in paintings in the tomb of Egyptian Pharaoh Ramses III (1198-1166 B.C.), in sculptures from ancient Greece, in votive carvings from Iraq which date from 2900 B.C. Likely during the growth of Islam, the harp traveled from north Africa to Spain during the 8th century; its use soon spread throughout Europe.

Strung with sinew, silk or wire, harps vary in size, structure and decoration according to the physical and technological environments of their origins. African harps have been made from a wide variety of materials including wood and gourd covered with cow or other animal hide. Some have a bow shaped or "arched" soundbox (that is, the body and resonator of the instrument) and string arm (the neck of the instrument which has tuning pegs attached to it), such as the horizontally held Burmese "sang-auk". The body of the Turkish "ceng" is also curved or "c-shaped". Since the medieval era, European harps have had a triangular frame - a column or "pillar" was added to the soundbox and string arm. There is one feature that all harps share: the strings run vertical (rather than parallel) to the sound box.
These instruments are central to the musical cultures of many communities, from Indonesia to Central America. In Jalisco, Mexico, the harp was significant in the development of mariachi music which originally featured only string instruments; In this and other Latin American countries (especially Guatemala and Ecuador), some suggest that harps were introduced during the 16th and 17th centuries by African slaves brought by Spanish explorers and colonists to central and North America.
In Britain, harps have also played a deeply symbolic role. Stone sculptures of small, portable Celtic harps date back to about 800 AD in Scotland. Since at least the 12 century, the harp has also been a powerful emblem for Irish nationalists. Prior to the 1700s, Irish harpists held a role of honor and considerable prestige in political circles and were often consulted before battles. In fact, they had such important political power that during the 16th century, Queen Elizabeth I issued a proclamation to arrest Irish harpists and destroy their instruments to prevent insurrection. According to the Irish Harp Foundation,
" Originally, the harper provided music to accompany the recitation of heroic verse at the Celtic chieftain's court. After the dissolution of old Gaelic society, the harper became a wandering minstrel performing in the 'big houses' of the aristocracy. Then, in the 18th and 19th century, the tradition evolved anew as Irish 'high society' played for its own entertainment. In the early 1950s, the Irish harp featured prominently in popular Irish entertainment promoted heavily throughout the world in the tourism industry - and in the late 1960s, the American folk music revival had its response in Ireland with the 'rediscovery' of Irish folk music. All of these developments in the Irish harp story are characterised by particular playing styles and repertoires."
The contemporary western orchestral harp is the product of an ancient heritage and centuries of technological innovations that constantly sought to improve its range and tone and the speed at which different tuning systems could be changed (through hook and pedal mechanisms). In North America, there has been a dramatic increase of interest in the harp since the 1950s. Among contemporary performers/teachers are Judy Loman, Toronto Symphony Orchestra; Lynne Aspnes, University of Michigan; Nancy Allen, Juliard School of Music; and Lucille Brais, University of Ottawa.