The Bansuri is considered to be divine and is intimately linked to lord Krishna and Radha. It is believed that when lord Krishna played his flute, the beautiful sound had a spellbinding and enthralling effect not only on men n women but also on all life forms.
The oldest flutes found, are thousands of years old and made of bones. These flutes were used during hunting and in magic rituals. Later on flutes are found which were made of wood or bamboo. All flutes used to have only holes. You could hold a flute to the left or right side and there were even flutes you could hold straight like a recorder.
Until the middle ages flutes were played by hunters, shepherds, musicians in festive occasions and from the 13th century on also by soldiers.From the 16th century on the flute developed into the modern flute which we know nowadays. In that time the flute was made in one piece and still didn't have any keys at all. About 1670 the flute became more and more popular. The flute was made in three pieces and got its first key: The d sharp key, which we still have on the modern flute; it is the key for your right little finger. This flute is nowadays called the barock flute. There used to be many intonation problems on the flute. This was not only because of the holes, but it was also caused by the different intonations (pitch) in different countries and cities. Therefore flutes were also available in 4 pieces after 1720. The shorter pieces were for playing much more sharp (higher pitch) and the longer pieces were for playing much more flat (lower pitch).
Because there was only one key on the flute you had to play with very complicated fingerings. Th ese fingerings are called fork fingerings and the tones of these fork fingerings sounded not too good. There came extra holes and keys on the flute to get rid of the fork fingerings. Around 1775 the flute had four keys: d sharp (already existed), b flat key, g sharp key and f key.
Eventually more and more keys were added to the flute, but there still wasn't a good system for the keys. The very famous English flautist Charles Nicholson (1795-1837) introduced larger holes for the fingers and a larger hole for the mouth piece in order to get a better sound.
The famous flute maker Theobald Boehm (1794-1881) once heard Charles Nicholson play in a concert. Boehm was so impressed by his sound that he started developing the flute further. In 1832 the flute with key mechanism by Theobald Boehm was ready. Boehm called this new flute Ringklappenflöte. With this mechanism playing the flute became much easier and the flute did sound much better.