The qanun (Arabic or Persian, also transcribed kanoun, kanun, kanon, kanonaki, qanun, quanoun, Kalong) is an instrument plucked the zither family table, widespread in the Middle East and Greece, Iran, Azerbaijan, Armenia and Chinese Turkestan. It must not be confused with the santur is a keyboard instrument. Qanûn the Arabic word derive from the Greek: κανών, Kanon (Measurement) which was also the name given to a monochord instrument for the study of intervals in music, already known to Pythagoras. The ancient history of qanûn is not well known. It is likely that the qanûn down from ancient harp. Some attribute it to the philosopher Al-Farabi in the late ninth century but no records to confirm this thesis. Others attribute it a Greek or Assyrian origin. In instrumental Byzantine music, that is to say, the secular art music of the Eastern Roman Empire (also known as the Byzantine Empire), the qanun existed in a form called "psaltirio" in Greek.