One of the most famous Royal Site is located at Tara, Co. Meath. The Hill of Tara has been home to druids, warriors and was the seat of the High Kings of Ireland. The Hill of Tara today has the ruins of the royal enclosures, and circular mound formations. Most of the sites at Tara were given fanciful names by 19th century antiquarians fired by images of Celtic warrior heroes and great battle feasts.  Hostage taking was a common method of controlling territory in Ireland.  Niall of the Nine Hostages who ruled at Tara at the beginning of the 5th century, was said to have taken one hostage from each of the five provinces of Ireland as well from the Scotts, the Saxons, the Britons and the French, hence the Mound of Hostages got his name.  This is the ancient passage cairn, which sits within the Rath of Kings at Tara and is the oldest monument on the site, having been built around 3000 BC.
Kings, poets and heroes used to gather at Tara every three years. There they would make laws, settle disputes and review the poems and stories that every poet kept in his head.