How were instruments generally used in Medieval and Renaissance vocal music?

During the Middle Ages and the Renaissance, the use of instruments in vocal music was primarily functional, serving to support or extend the vocal lines rather than acting as independent entities.

Medieval Usage

In the medieval period, instruments were frequently used to accompany singing and dancing. Their role was largely auxiliary; they often doubled vocal parts or substituted for voices in polyphonic music. Because medieval composers generally lacked rigid expectations regarding performance media, the choice of instruments often depended on the performers available. Musicians typically categorized instruments into "loud" (haut) and "soft" (bas) groups, selecting them based on whether the performance was outdoors or indoors. Secular music often featured instruments providing rhythmic support or a drone, while liturgical music occasionally incorporated organs.123

Renaissance Usage

During the Renaissance, while instruments continued to double or substitute for voices, an independent instrumental idiom began to emerge. Instrumental ensembles, such as consorts of viols or woodwinds, became common, though mixed ensembles were frequently used depending on availability. By the 16th century, solo songs were often performed with simple lute accompaniments that could be either chordal or contrapuntal.243