High Kings were the supreme rulers in ancient Ireland, overseeing multiple kingdoms and tribes. They were often chosen from powerful families and held authority over the land, making decisions that affected all the people. The title of High King was not hereditary; instead, it was based on a combination of lineage, strength, and support from other chieftains. The concept of the High King is closely linked to Irish mythology and history, where figures like Brian Boru are celebrated for their leadership. High Kings were responsible for maintaining peace and order, often leading their warriors in battle and representing their people in diplomatic matters.