ieExplains: What is an Ard Fheis and why are they deemed important?

What exactly happens at an Ard Fheis and why do political parties still see them as one of the most important events in the calendar?

Leo Varadkar speaks at the Fine Gael Ard Fheis last year. Picture: Sam Boal/RollingNews.ie

Ard Fheis season is in full swing, but what exactly happens at an one? And why do political parties still see them as one of the most important events in the calendar?

What is an Ard Fheis?