However, the prominence given to Rath Oinn in the accounts shows that it must have been an important centre in the distant, poorly-remembered past.

[11] The Lebor Gabála Érenn (11th century) also states that "Rath Oinn in the land of Cualu was dug by Érimón.

[citation needed] Henry II granted the Manor of Rathdown to Donal as tenant-in-chief.

[14] Associated with the castle was a village of several hundred people with a mill and a church (St. Crispin's Cell; the current building dates to 1530).

[17][18] Rathdown Castle and village survived to the early 1600s, being the subject of occasional raids by Gaelic tribes, such as the O'Byrnes and O'Tooles of the Wicklow Mountains region.