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).