of Munster to the south and west. Some of the highest points of land are Brandon Hill (County Kilkenny) and Arderin (on the Laois-Offaly border). The ancient Slige Dala road ran southwest through northern Osraige from the Hill of Tara towards Munster; which later gave its name to the medieval Ballaghmore Castle. Another ancient road, the Slighe Cualann cut into southeast Osraige west of present-day Ross, before turning south to present-day Waterford city. History Origins and prehistory The tribal name Osraige means "people of the deer", and is traditionally claimed to be taken from the name of the ruling dynasty's semi-legendary pre-Christian founder, Óengus Osrithe. The Osraige were probably either a southern branch of the Ulaid or Dál Fiatach of Ulster, or close kin to their former Corcu Loígde allies. In either case it would appear they should properly be counted among the Érainn. Authoritative scholars, such as T. F. O'Rahilly believed that the Lagin pedigree of the Osraige is a fabrication, invented to help them achieve their goals in Leinster. Francis John Byrne suggests that it may date from the time of Cerball mac Dúnlainge. The Osraighe themselves claimed to be descended from the Érainn people, although scholars propose that the Ivernic groups included the Osraige. Prior to the coming of Christianity to Ireland, the Osraige and their relatives the Corcu Loígde appear to have been the dominant political groups in Munster, before the rise of the Eóganachta marginalized them both. Ptolemy's 2nd-century map of Ireland places a tribe he called the "Usdaie" roughly in the same area that the Osraige occupied. The territory indicated by Ptolemy likely included the major late Iron Age hill-fort at Freestone Hill and a 1st-century Roman burial site at Stonyford, both in County Kilkenny. Due to inland water access via the Nore, Barrow and Suir rivers, the Osraige may have experienced greater intercourse with Britain and the continent, and there appears to have been some heightened Roman trading activity in and around the region. Such contact with the Roman world may have precipitated wider exposure and later conversion to Early Christianity. From the fifth century, the name Dál Birn ("the people of Birn"; sometimes spelt dál mBirn) appears to have emerged as the name for the ruling lineage of Osraige, and this name remained in use through to the twelfth century. From this period, Osraige was originally within the sphere of the province