Tethbae (pronounced [ˈteθve]; also spelled Tethba, often anglicised Teffia) was a confederation of túaithe in central Ireland in the Middle Ages. It was divided into two distinct kingdoms, north Tethba, ruled by the Cenél Coirpri, and south Tethba, ruled by the Cenél Maini. It covered parts of County Westmeath and much of County Longford, counties which today are the far north-west part of the province of Leinster.
In some cases Tethbae may refer to south Tethbae only.
In Early Christian times, Tethba lay within the lands of the southern Uí Néill and the ruling dynasties of both kingdoms were reckoned members of the Uí Néill kindred in medieval genealogies. North Tethba—Tethbae Thúaiscirt—was centred on Granard, while south Tethba—Tethbae Deiscirt—lay around Ardagh.
The division of Tethbae into northern and southern regions was attested in the 7th century. It was not only a political and dynastic division. The chief churches of the two-halves belonged to different church confederations. North Tethbae's principal church at Granard was associated with Saint Patrick from the earliest written records. Bishop Tirechán's hagiography refers to "the two Tethbae" and claims that Patrick established bishops at both Granard and Ardagh. But although Granard is included among the network of Patrician churches, Ardagh is not. The key figure in Ardagh tradition was its founder, Bishop Mél, according to Patrician accounts a nephew of Patrick. Ardagh, by the time of Tirechán and the earliest records, was a part of the confederation of churches which took Brigit of Kildare as chief patron and looked mainly to the church at Kildare for leadership.
Medieval Irish traditions presented the lands of the Uí Néill as conquests by Niall of the Nine Hostages and his sons. Niall's son Coirpre was the eponymous ancestor of Cenél Coirpri. Along with Fiachu, he may have led the earliest Uí Néill conquests in the midlands.
North Tethbae, Cenél Coirpri Mór, was one of three kingdoms named for Coirpre mac Néill. To the north-west of Tethbae, on the shore of Donegal Bay, was the kingdom of Cenél Coirpi Dromma Clíab. To the south-east, in County Kildare, around Carbury, itself named for Coirpre, was a third branch of Cenél Coirpi but this was not established until much later. This alignment of territories, together with the evidence of the Irish annals, which include a series of entries crediting Coirpre with the conquest of the midlands, suggests that the kingdom of Coirpre once extended over 100 miles across Ireland.
Apart from Coirpre himself and his grandson Túathal Máelgarb, no king of Cenél Coirpri is included in later lists of High Kings of Ireland. Later kings of Cenél Coirpri are mentioned in the Annals of Ulster and other Irish annals with some frequency, although usually only to report their deaths. Most kings are simply called "king of Cenél Coirpri", although Conaing (died 752) is specifically called "king of Coirpri of Tethbae". An entry in 799 reporting the deaths of two kings of Coirpri, Murchad ua Cathail and Dub Innrecht mac Artgaile, shows that the kingship could be shared. In addition to the usual annalistic reports, Óengus Bronbachall, grandson of Túathal, is mentioned in Adomnán's Life of Saint Columba.
At least in earlier historical times, Cenél Coirpri may have been of sufficient importance to attract the attention of largely hostile writers. Tirechán's life of Patrick states that Coirpre was cursed by the saint, at the hill of Tara, that none of his descendants would be High King. Túathal Máelgarb is portrayed in a poor light by later writers dealing with the life of Diarmait mac Cerbaill, his perhaps-kinsman whose descendants, Clann Cholmáin and the Síl nÁedo Sláine, replaced the kindreds of Coirpre and Fiachu as rulers of the midlands.
In the 11th century, north Tethbae was largely absorbed by the expanding kingdom of Bréifne, ruled by the Ua Ruairc branch of the Connachta kindred of Uí Briúin, and its clients the Conmaicne Réin.
While Coirpe mac Néill is a major figure in the annals and appears in Tirechán's hagiography, Maine son of Niall is not mentioned by Tirechán, nor is their any record of his conquests. It may be, and is perhaps even probable, that descent from Niall of the Nine Hostages through an otherwise poorly attested line of descent is a genealogical fiction designed to strengthen Uí Néill control of the midlands. The Cenél Maini probably originated as part of a much larger Uí Maine kingdom extending from the eastern part of modern County Galway through County Roscommon, across the River Shannon, and into County Longford.
Although officially incorporated into the Uí Néill, no king of Cenél Maini was ever reckoned a High King of Ireland. The Vita tripartita Sancti Patricii does, however, say that the kings of Cenél Maini had a privileged place in choosing and inaugurating High Kings, much like the Airgíalla, another group believed to have been associated with the Connachta, of which the Uí Néill were only the leading group, by genealogical fictions.
- Byrne, Irish Kings, p. 89; Charles-Edwards, Early Christian Ireland, pp. 16 & 33; McKillop, "Tethbae".
- Charles-Edwards, Early Christian Ireland, p. 36; De Paor, Saint Patrick's World, pp. 159 & 198.
- Charles-Edwards, Early Christian Ireland, pp. 33 & 260.
- Byrne, Early Christian Ireland, pp. 84 & 90–91; Charles-Edwards, Early Christian Ireland, pp. 447–451.
- Byrne, Irish Kings, pp. 84–91 & additional notes at p. xvi; Charles-Edwards, Early Christian Ireland, p. 469.
- Charles-Edwards, Early Christian Ireland, pp. 607–68, genealogical table VI (Cenél Coirpri) & notes; for Óengus Bronbachall, see the Life of Saint Columba, book I, chapter 13.
- De Paor, Saint Patrick's World, p. 156. The obvious omission, an explanation for the rule of Túathal Máelgarb, was corrected by later hagiographers; Charles-Edwards, Early Christian Ireland, pp. 33–34. In the earliest surviving list, that in the Baile Chuind, Túathal appears not under his own name but as Óengarb; Byrne, Irish Kings, pp. 90–92.
- Byrne, Irish Kings, pp. 90–92; Charles-Edwards, p. 468.
- Byrne, Irish Kings, p. 92 & 233–237; MacKillop, "Conmaicne". It may be that the Conmaicne Réin were simply retaking lands which had once been theirs.
- Byrne, Irish Kings, pp. 85 & 92–93; Charles-Edwards, Early Christian Ireland, pp. 96 & 548; Ó Cróinín, Early Medieval Ireland, p. 61.
- Charles-Edwards, Early Christian Ireland, pp. 34–35, 96 & 548–549.
- Byrne, Francis John (2001), Irish Kings and High-Kings (2nd ed.), Dublin: Four Courts Press, ISBN 1-85182-552-5
- Charles-Edwards, T. M. (2000), Early Christian Ireland, Cambridge: Cambridge University Press, ISBN 0-521-36395-0
- De Paor, Liam (1993), Saint Patrick's World: The Christian Culture of Ireland's Apostolic Age, Dublin: Four Courts, ISBN 1-85182-144-9
- MacKillop, James (1998), The Oxford Dictionary of Celtic Mythology, Oxford: Oxford University Press, ISBN 0-19-860967-1
- Ó Cróinín, Dáibhí (1995), Early Medieval Ireland: 400–1200, London: Longman, ISBN 0-582-01565-0