Flutes and Pipes in some form have been played in Ireland by the Celts for at least 1,000 years prior to the more modern instruments we see today. Fragments of flutes and whistles dating to 1,000AD have been excavated in Dublin, Cork and Waterford.

But the Irish flute that you see today in traditional sessions is essentially a very close cousin to the wooden transverse Baroque style flute that was widely popular throughout Europe in the 1700's. The baroque flute was a conical bore instrument in the key of D, with six rather small finger-holes and one key (E-flat). This was the chamber instrument of Beethoven’s day (1770-1827) and Mozart (1756-1791). Baroque flutes continued to be developed and refined until the mid 19th Century.

Chris Horgan's Irish Flute

In 1831 a German designer, Theobald Boehm, created the Boehm system – which is the silver flute you seen on Orchestras these days. It is made of metal and has a lot of mechanical keys.

When the orchestral musicians of Europe changed over to the Boehm flute, it is said that the old wooden open holed flutes began to show up in pawn shops for low prices, where the Irish could afford to buy them. Irish makers could also easily make the wooden flutes and have continued to experiment and evolve their designs.

The majority of Irish flutes of today are generally close copies of one of two makes of wooden flute; Rudall & Rose (c1820) or Pratten (c1840). 

The modern "Clarke Tin Whistle" made its appearance 1840. It has the same fingering as the Irish Flute.

As quoted by an unknown, insightful author…

“Never get one of those cheap tin whistles. It leads to much harder vices like pipes and flutes.”