The viol (also called viola da gamba) is any one of a family of bowed, fretted stringed musical instruments developed in the 1400s and used primarily in the Renaissance and Baroque periods. The family is related to and descends from the vihuela and rebec.

It is thought that vihuelists began playing their instruments with a bow in the 15th century. This eventually led to the evolution of an entirely new instrument, which had many of the features of the vihuela: flat back, frets and arched bridge (hence its Spanish name vihuela de arco), but was bowed rather than plucked. This new instrument began to be held upright, either resting on the lap or held between the legs like a cello. This gave rise to its Italian name viola da gamba, for "viol of the leg." This differentiates it from the similar but only distantly related violin family, known earlier as the lira da braccio or viola da braccio (lit. "viol of the arm") family. During the Renaissance, the viola da braccio was considered to be inferior to the viol as an instrument.

One of the earliest illustrations of viols is in an altarpiece by Lorenzo Costa, in the church of San Giovanni in Monte in Bologna. This picture, dated 1497, includes a depiction of two young musicians playing viols: the curved bridges, use of bows and resting the instruments on the players' legs all mark these instruments out as early viols.

The bow is held underhand (palm up), similar to a German double bass bow grip, but away from the frog towards the balance point. The stick's curvature is generally convex as were violin bows of the period, rather than concave like a modern violin bow. The "frog" (which holds the bowhair and adjusts its tension) is also different from that of modern bows: whereas a violin bow frog has a "slide" (often made of mother of pearl) to hold the hair flat across the frog, viol bows have an open frog that allows more movement of the hair. This is essential to allow the traditional playing technique in which the player tensions the bow hair with one or two fingers of the right hand between the hair and the bow stick in order to control articulation and inflection while playing.

The instrument was common among amateurs, and many homes would have a so-called chest of viols which would contain one or more instruments of each size. Gamba ensembles, called consorts, were common in the 16th and 17th centuries, when they performed vocal music (consort songs or verse anthems) as well as that written specifically for instruments. Only the treble, tenor, and bass sizes were regular members of the viol consort, which consisted of three, four, five, or six instruments. Music for consorts was very popular in England in Elizabethan times, with composers such as William Byrd, John Dowland and during the reign of King Charles I by composers such as John Jenkins and William Lawes. The last music for viol consorts before their modern revival was probably that written in the early 1680s by Henry Purcell.


There are several important treatises concerning the viol. The first was by Silvestro Ganassi: Regola Rubertina & Lettione Seconda (1542/3). Diego Ortiz published Trattado de Glosas (Rome 1553), an important book of music for the viol with both examples of ornamentation and pieces called Recercadas. In England, Christopher Simpson wrote the most important treatise, with the second edition being published in 1667 in parallel text (English and Latin). This has divisions at the back which are very worthwhile repertoire. A little later in England, Thomas Mace wrote Musick's Monument, which deals more with the lute, but also has an important section on the viol. After this the French treatises by Rousseau (1687), Danoville (1687) and Loulie (1700) show further developments in playing technique.

The bass viola da gamba continued to be used into the 18th century as a solo (music) instrument and to complement the harpsichord in basso continuo). It was a favorite instrument of Louis XIV and acquired associations of both courtliness and Frenchness (in contrast to the Italianate violin). Composers such as Marin Marais, Johann Sebastian Bach, and Karl Friedrich Abel wrote virtuoso music for it. However, viols fell out of use as concert halls grew larger, and the louder and more penetrating tone of the violin family became more popular. In the last one hundred years or so, the viola da gamba and its repertoire were revived by early music enthusiasts, an early proponent being Arnold Dolmetsch.