O' • Sullivan • Sullavan • Sullivant • Sillivant • Silliphant • Sillifant • Súileabháin • Súilleabháin
- O'Sullivan (Irish Ó Súileabháin or Ó Súilleabháin) or simply Sullivan is an Irish surname, associated with the southwestern part of Ireland, originally found in County Tipperary before the Anglo-Norman invasion, then in County Cork and County Kerry, which due to emigration is also common in Australia, North America and Britain. The O'Sullivans are the medieval and modern continuation of the ancient Eóganacht Chaisil sept of Cenél Fíngin, being descendants of Fíngen mac Áedo Duib, king of Cashel or Munster from 601 to 618. They are thus understood to be of royal extraction. Fedelmid mac Crimthainn (died 847), the celebrated King of Munster and nearly High King of Ireland, was the last king of the Cenél Fíngin/O'Sullivan line. Later they became the chief princes underneath their close kinsmen the MacCarthy dynasty in the small but powerful Kingdom of Desmond, successor of Cashel/Munster.
- In the last 200 or 300 years those families connected to the name have dispersed widely throughout the English-speaking world and to other areas. Emigrants often suppressed the prefix "O".
- In the Irish language the word Ó means 'grandson' and can be found in many Irish surnames. It has been anglicised as O'. When placed before the genitive form of Súileabhán, which is Súileabháin, it can be translated as grandson of. While the use of an apostrophe is a common convention in English, the apostrophe is never used in the original Irish language version of the name.
- According to Woulfe in Sloinnte Gaedheal is Gall Ó Súileabháin (the genitive form of súileabhán being súileabháin) derives from the Irish Ó which comes from Ua meaning grandson and súildubhán meaning little dark-eyed one, from the Irish súil meaning eye followed by dubh meaning black and the diminutive suffix -án.
- Edward MacLysaght states in The Surnames of Ireland that while there is no doubt that the basic word is súil (eye) there is a disagreement as to the meaning of the last part of the name.
- Some O'Sullivans in the midlands and south Ulster were originally (O) Sullahan (from Ó Súileacháin (probably from súileach, quick eyed, according to MacLysaght. This surname has now almost entirely changed to Sullivan.
- MacLysaght also tells us that Mac Criomhthain (MacCrohan) and Mac Giolla Chuda (MacGillycuddy) are important branches of the Súileabhánaigh in Co Kerry.
- The motto for the O'Sullivans is "An Lámh Fhoisteanach Abú" which translates as "The Steady Hand to Victory".
- Variations on the name include: Sullavan, Sullivant, Sillivant, Silliphant, and Sillifant.