The first referendum in the series leading to the same-sex marriage vote was on EU membership. A song parody from then: "A Province Once Again"
"For freedom lives at God's right hand
And Satan rules in Brussels..."
The irony is that it took Henry II and the Norman invasion to finally drive out the openly pagan elements and make all of Ireland fully Catholic. And from that point forward, the lordship of Ireland was granted to the English monarch by the Papacy, nullifying the power of the High King and regional kings such as the King of Leinster who pledged fealty to Henry II in exchange for regaining his position.