Florentine Camerata
Theorbos were developed during the late sixteenth century in Italy, inspired by the demand for extended bass range instruments for use in the then-newly developed musical style of opera developed by the Florentine Camerata and new musical works utilising basso continuo, such as Giulio Caccini's two collections, "Le nuove musiche" (1602 and 1614). For his 1607 opera "L'Orfeo", Claudio Monteverdi lists "duoi" (two) "chitaroni" among the instruments required for performing the work. Musicians originally used large bass lutes (c. 80+ cm string length) and a higher re-entrant tuning; but soon created neck extensions with secondary pegboxes to accommodate extra open ("i.e." unfretted) longer bass strings, called "diapasons" or "bourdons", for improvements in tonal clarity and an increased range of available notes.