[1][2] This illustrious lineage produced Osraige's native kings and lords- all claimed to be commonly descended on the paternal line from the second-century king Loegaire Birn Buadach (Loegaire Birn "the Victorious"), son of Óengus Osrithe and gave rise to a number of related individuals and later, clans which remained intact and identifiable into the modern era.
The term Dál Birn was in use long before the advent of surnames in Ireland, yet because of long-standing oral and written traditions in Ireland, it continued to be used as a mark of hereditary distinction in sources composed through the twelfth century after the common advent of surnames.
For a two-hundred year period beginning the late fifth century, the native Dál Birn kings were temporarily displaced by an allied Corcu Loígde dynasty which ruled Osraige until finally being overthrown.
A number of the Corcu Loígde kings are recorded as being periodically slain by the native inhabitants of Osraige until the re-establishment of the Dál Birn.
In addition to all the native Ossorian kings (not counting the Corcu Loígde), a number of other notable family names descend from Dál Birn: