Each Irish kingdom is thought to have had its own royal site, but six sites are considered to be the most important. Four of these served as the royal sites of the four major provinces of Ireland. Cashel for Munster, Navan Fort for Ulster, Dún Ailinne for Leinster, and Carnfree of the Rathcroghan for Connaught. The Hill of Tara served as the seat for the Kings of Meath and the seat of the High King. Respectively, these sites are known in medieval sources as Caisel, Emain Macha, Dun Ailinne (Knockaulin), Cruiachain (Cruachu), and Teamhair. Uisneach represented the union of the provinces and may have served as a meeting place for the kings. The major sites, excluding Navan Fort (located in Northern Ireland), have been listed as a potential UNESCO World Heritage Site.