That Ireland was reasonably well known in the classical world is demonstrated by Ptolemy’s Geography. This is a list of place names and tribal names with their exact locations given in longitude and latitude. It was compiled by Ptolemy who was a Roman living in Alexandria, Egypt, during the 2nd century AD. From the information given in the list it is possible to reconstruct of map of Ireland that appears strikingly familiar (above). Indeed, a number of the names on the list are still easily recognisable (especially the rivers). Buvinda, is the Boyne, Senos is the Shannon, Logia is the Lagan, Obboca is the Avoca river (or possibly the Liffey), while Limnos may be Lambey island. It has also been suggested that the northern Regia shown on the map might represent Clogher hillfort, while Raeba may be the royal site of Cruchain, and Ivernis could be Cashel
Roman contacts with Ireland (Irish Archaeology)