The alternative suggestion is that the name derives from the 'O’Flannan tribe': in August 1931, in the Proceedings of the Royal Irish Academy, a paper referencing a 15th-century manuscript (itself said to be a copy of a 12th-century document) listing rents in Clanmaurice presents both 'O Flannayn' and 'Kyllflanyn' as 'Kilflyn' in the English translation from the original Latin, a significant error which may be the root of the suggestion. The cantred (cf. Welsh cantref or English hundred) or rural deanery of Othorna & Oflannan (Irish Uí Thorna & Uí Flannáin) was an Anglo-Norman sub-division, in this case generally along the historical boundaries of much older kingdoms and regions which were part of West Munster (Irish Iarmuman or Iar Mbumba), in the realm of the Ciarraighe, and which later became County Kerry some time between 1222 and 1229.