A quote from the Lark in the Morning catalog:
The pennywhistle, also called the tinwhistle or flageolette, is a very ancient instrument going back to prehistoric times with surviving instruments made of bone. These instruments are very popular in the British Isles. They have a fipple like a recorder and are very easy to make music with, yet lend themselves to a great deal of creativity & virtuosity as well. The perfect pocket instrument.
I suspect that the pennywhistle and the transverse 6-hole flute (or fife) are co-ancient and the recorder, being more complicated, is a later refinement of the whistle. Of course, the ancient bone whistles referred to probably had a different scale than our modern diatonic scale.
Another Jon (Jon W.)