The Wearing Of The Green (Marie Narelle)
The Wearing Of The Green (Wolfetones)
The Wearing Of The Green (Orthodox Celts)
"The Wearing of the Green" is an anonymous Irish street ballad dating to 1798. The context of the song is the repression around the time of the Irish Rebellion of 1798. Wearing a shamrock in the "caubeen" (hat) was a sign of rebellion and green was the colour of the Society of the United Irishmen, a republican revolutionary organisation. During the period, displaying revolutionary insignia was made punishable by hanging. (from en.wikipedia)

This is the 1864 version by Dion Boucicault, written for his 1864 play "Arragh na Pogue", or "The Wicklow Wedding".