https://app.box.com/s/54zr4eqb87vschqem0namd9n0fmgj2dl
A Picardy third also known as a Picardy cadence, is a major chord of the tonic at the end of a musical section that is either modal or in a minor key.
I played this 16 century carol in the key of G minor . I think that I played my last chord as G major. which means I finished with a Picarde third.
The music contains a well-known example of a Picardy third. The author is unknown; the oldest known text was written down by Robert Croo in 1534, and the oldest known setting of the melody dates from 1591.[1] There are alternative, modern settings of the carol by Kenneth Leighton and another by Philip Stopford.
I found the above quotes on Wikipedia, and I must get around to sending them a donation. J.T.