Creassa inion Urchadh
Creassa was a daughter of King Urchadh mac Murchadh of Maigh Seóla (reigned 891?-943). She was married to King Tadg mac Cathail of Connacht (reigned 925-956). By him, she had sons Conchobar mac Tadg, Máel Ruanaid Mór mac Tadg and Tadg.
Each of her three sons would found important Connacht dynasties; Máel Ruanaid Mór's would become Kings of Moylurg, while Tadg's descendants would become royal marshals and bodyguards of the kings of Connacht, such as Fearghal Ó Taidg an Teaghlaigh.
The most notable would descend from Conchobar, whose descendants would take his name as their surname, O'Connor. This line of the family would remain Kings of Connacht into the 15th century; two of them - Toirdelbach Ua Conchobair (1088–1156) and Ruaidrí Ua Conchobair (died 1198) - would become High Kings of Ireland.
Her sisters Bé Binn inion Urchadh and Caineach inion Urchadh similarly made good marriages, while her brother, Donnchadh mac Urchadh was King of Maigh Seóla (943-959). He was the ancestor of the O'Flaherty family and their related septs.
- West or H-Iar Connaught Ruaidhrí Ó Flaithbheartaigh, 1684 (published 1846, ed. James Hardiman).
- Origin of the Surname O'Flaherty, Anthony Matthews, Dublin, 1968, p. 40.
- Early Irish Kingship and Succession, Bart Jaski, Four Courts Press, 2000.
- Irish Kings and High-Kings, Francis John Byrne (2001), Dublin: Four Courts Press, ISBN 978-1-85182-196-9
- The Great Book of Irish Genealogies, Dubhaltach Mac Fhirbhish: Edited, with translation and indices by Nollaig Ó Muraíle Five volumes. Dublin, DeBurca, 2004-2005. ISBN 0 946130 36 1.