playing their flat-edged 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 originally plucked vihuela: a flat back, sharp waist-cuts, frets, thin ribs (initially), and an 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. Stefano Pio argues that a re-examination of documents in the light of newly collected data indicates an origin different from the vihuela de arco from Aragon. According to Pio, the viol (viola da gamba) had its origins and evolved independently in Venice. Pio asserts that it is implausible that the vihuela de arco (which possibly arrived in Rome and Naples after 1483–1487, since Johannes Tinctoris does not mention it before this time) underwent such a rapid evolution by Italian instrument makers – not Venetian (circumstances specifically excluded by Lorenzo da Pavia), nor Mantuan or Ferrarese (as evidenced by Isabella and Alfonso I d'Este's orders from luthiers from other cities) – so that 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 both in the manuscript of the early 15th-century music theorist Antonius de Leno and the treatises of the Venetian Silvestro Ganassi dal Fontego and , the fifth string of the viola da gamba is uniquely called a bordone (drone), although it is not a drone and is played the same as the other strings. Pio argues that this inconsistency is justifiable only assuming the invention, during the last part of the fifteenth century, of a larger instrument derived from the medieval violetta, to which was gradually added other strings to allow a greater extension to the low register that resulted from its increased size. The fifth string, already present in some specimens of these violette as a drone (bordone), was incorporated into the neck when they were expanded in size. This was then surpassed by a sixth string, named basso, which fixed the lower sound produced by the instrument. In Pio's view, the origin