The viol (also viola da gamba, Italian: [ˈvjɔːla da (ɡ)ˈɡamba, viˈɔːla -], or informally gamba) is a family of bowed, fretted string instruments that developed in Spain in the late 15th century, particularly in Valencia within the Crown of Aragon, and subsequently spread to Italy and other parts of Europe. Most viols have six strings tuned primarily in fourths, with a third in the middle, and are played upright, with the instrument held on or between the legs—hence the Italian name viola da gamba, meaning "leg viol".
Viols are distinguished from instruments of the violin family by features including their frets, tuning, generally flat backs and sloping shoulders, and the use of an underhand bow grip. The family developed in several sizes, most commonly treble, tenor and bass, and became widely used during the Renaissance and Baroque periods as solo, consort and continuo instruments.
The early development of the viol was closely connected with the vihuela, a family of Spanish string instruments that could be played with the fingers, a plectrum or a bow. Bowed vihuelas were established in the Crown of Aragon by the late 15th century and contributed to the emergence of the viol family, which underwent further development in Italy during the 16th century.
The term viola da gamba may refer to the viol family as a whole, although without qualification it commonly refers to the bass viol. Viols remained prominent in European art music through the 17th and 18th centuries before declining in use, and were revived in the 20th century as part of the historically informed performance movement.
Vihuelists began playing their flat-topped, originally plucked, instruments with a bow in the second half of the 15th century. Within two or three decades, this led to the evolution of an entirely new and dedicated bowed string instrument that retained many of the features of the vihuela: e.g., a flat back, sharp waist-cuts, frets, thin ribs initially, and identical tuning—hence its original name, vihuela de arco; arco is Spanish for "bow". An influence on the playing posture has been credited to the example of Moorish rabab players.
However, Stefano Pio (2012) argues that a re-examination of documents in light of new data indicates an origin different than the vihuela de arco from Aragon. According to Pio, the viol had its origins in Venice, and evolved independently there. He asserts it was implausible that the vihuela de arco underwent such a rapid evolution by Italian rather than Venetian instrument makers. Nonetheless, a ten-year span brought the birth and diffusion in Italy of a new family of instruments (viola da gamba, or viols). These comprised instruments of different sizes, some as large as the famous violoni—as 'big as a man'—mentioned by Prospero Bernardino in 1493.
Pio also notes that the fifth string of the viola da gamba is uniquely called a bordone (drone)—both in the manuscript of the early 15th-century music theorist Antonius de Leno, and in the treatises of the Venetian Silvestro Ganassi dal Fontego and Giovanni Maria Lanfranco. However, it is not a drone and is played the same as the other strings. This inconsistency is justified, Pio argues, only by assuming the invention (in the latter 15th century) of a larger instrument derived from the medieval violetta, which gradually added more strings to allow greater extension to the low register. The fifth string was incorporated into the neck. This was surpassed by a sixth string (basso) which fixed the lower sound produced by the instrument. Pio's view was: the origin of the viola da gamba is tied to the evolution of the smaller violetta, or vielle, which was originally fitted with a fifth-string "drone"; and the name 'stuck' even after it ceased to perform this function.
Ian Woodfield, in his The Early History of the Viol, points to evidence that the viol does start with the vihuela, but that Italian luthiers immediately began to apply their own highly developed instrument-making traditions to the early version of the instrument after it was introduced into Italy.
Viols most commonly have six strings, although many 16th-century instruments had only four or five strings, and during the 17th century in France, some bass viols featured a seventh lower string. Viols were (and are) strung with gut strings of lower tension than on the members of the violin family. Gut strings produce a sonority far different from steel, generally described as softer and sweeter. Around 1660 in Bologna, gut or silk core strings overspun with copper wire first became available; these were then used for the lowest-pitched bass strings on viols, and many other string instruments as well. In 1664, a style of string incorporating a copper wire spun within the gut fibers, called a 'gimped' string, was introduced, mimicking the style of embroidery of the same name.
Viols are fretted like early guitars or lutes, using movable wrapped-around and tied-on gut frets. A low seventh string was supposedly added in France to the bass viol by Monsieur de Sainte-Colombe (c. 1640–1690), whose students included the French gamba virtuoso and composer Marin Marais. Also, the painting Saint Cecilia with an Angel (1618) by Domenichino (1581–1641) shows what may be a seven-string viol.
Unlike members of the violin family, most of which are tuned in fifths, viols are usually tuned in fourths with a major third in the middle, mirroring the tuning employed on the vihuela de mano and lute during the 16th century and similar to that of the modern six-string guitar.
Viols were first constructed much like the vihuela de mano, with all surfaces, top, back, and sides made from flat slabs or pieces of joined wood, bent or curved as required. However, some viols, both early and later, had carved tops, similar to those more commonly associated with instruments of the violin family. The ribs or sides of early viols were usually quite shallow, reflecting more the construction of their plucked vihuela counterparts. Rib depth increased during the 16th century, finally coming to resemble the greater depth of the classic 17th-century pattern.
The flat backs of most viols have a sharply angled break or canted bend in their surface close to where the neck meets the body. This serves to taper the back (and overall body depth) at its upper end to meet the back of the neck joint flush with its heel. Traditional construction uses animal glue, and internal joints are often reinforced with strips of either linen or vellum soaked in hot animal glue—a practice also employed in early plucked vihuela construction. The peg boxes of viols (which hold the tuning pegs) were typically decorated either with elaborately carved heads of animals or people or with the now-familiar spiral scroll finial.
The earliest vihuelas and viols, both plucked and bowed, all had sharp cuts to their waists, similar to the profile of a modern violin. This was a key and new feature—first appearing in the mid-15th century—and from then on, it was employed on many different types of string instruments. This feature was also key in seeing and understanding the connection between the plucked and bowed versions of early vihuelas. If one were to go searching for very early viols with smooth-curved figure-eight bodies, like those found on the only slightly later plucked vihuelas and the modern guitar, they would be out of luck. By the mid-16th century, however, "guitar-shaped" viols were fairly common, and a few of them survive.
The earliest viols had flat, glued-down bridges just like their plucked counterpart vihuelas. Soon after, however, viols adopted the wider and high-arched bridge that facilitated the bowing of single strings. The earliest of viols would also have had the ends of their fretboards flat on the deck, level with or resting upon the top or soundboard. Once the end of their fretboards was elevated above the top of the instrument's face, the entire top could vibrate freely. Early viols did not have sound posts, either (again reflecting their plucked vihuela siblings). This reduced damping again meant that their tops could vibrate more freely, contributing to the characteristic "humming" sound of viols. However, the absence of a sound post also resulted in a quieter and softer voice overall.