In the Golden Age the reputation of lutenists and other musicians would have been based mainly on their virtuosity, meaning both their skills as instrumentalists and their ability to improvise with convincing musicality. The practice of musicians was built largely around improvisation. At weddings and parties they would have played mainly dances, which were often based on a fixed harmonic pattern, or at least a fixed rhythmic outline, that provided musicians with an adequate framework for giving shape to musical ideas on the spot. In the case of aubades or private concerts, the repertoire may have consisted more of intabulations, settings for lute of well-known vocal works, and variations on popular tunes. Sweelinck, for instance, is known to have entertained his friends one evening with no fewer than 25 variations on the song De lustelijke mei [The lusty May]. It is not known whether Sweelinck ever noted down those ideas, but even if he did so, the work has not survived.

The pride musicians took in this skill is shown by the fact that they sometimes refer to it explicitly in improvisations that are written down. For instance, Vallet ‘signed’ a notarial deed with a two-part improvised canon (Canon Ex tempore A deux). And we have a toccata in Van den Hove's own hand that he improvised on 14 July 1615 (Joachim Vanden Hove Extempore Fecit Anno 1615 14-7). Although not a professional musician, Constantijn Huygens prides himself in his autobiography that soon after getting the hang of the lute, he could successfully ‘give free rein to my own aptitude and improvisational skills. This allowed me to play music nobody had ever heard before and which welled up within me with ease’. The majority of such improvisations, and therefore most of the instrumental music played at the time, would never have been written down.

A few centuries later, we modern music-lovers can only judge the 17th-century musicians on the basis of the works they actually wrote down, and which have also had the good fortune to survive. Many lutenists (to restrict ourselves to these musicians again) would have written down their music fairly regularly, for example when giving lessons to their pupils, in order to provide them with study material.