String instrument rosin than players of lower-pitched instruments, who tend to favor darker, softer rosin. The ravanahatha is one of the oldest string instruments. Ancestors of the modern bowed string instruments are the rebab of the Islamic Empires, the Persian kamanche and the Byzantine lira. Other bowed instruments are the rebec, hardingfele, nyckelharpa, kokyū, erhu, igil, sarangi and K'ni. The hurdy-gurdy is bowed by a wheel. Rarely, the guitar has been played with a bow (rather than plucked) for unique effects. The third common method of sound production in stringed instruments is to strike the string. The piano and hammered dulcimer use
Hurdy-gurdy Is Made), known through a much later copy, but its authenticity is very doubtful. Another 10th-century treatise thought to have mentioned an instrument like a hurdy-gurdy is an Arabic musical compendium written by Al Zirikli. One of the earliest visual depictions of the organistrum is from the twelfth-century "Pórtico da Gloria" (Portal of Glory) on the cathedral at Santiago de Compostela, Galicia, Spain: it has a carving of two musicians playing an organistrum. Later on, the "organistrum" was made smaller to let a single player both turn the crank and work the keys. The "solo organistrum" was known from Spain