The Deirgtine or Clanna Dergthened were the proto-historical ancestors of the historical Eóganachta

Eóganachta

The Eóganachta or Eoghanachta were an Irish dynasty centred around Cashel which dominated southern Ireland from the 6/7th to the 10th centuries, and following that, in a restricted form, the Kingdom of Desmond, and its offshoot Carbery, well into the 16th century...

 dynasties of Munster

Munster

Munster is one of the Provinces of Ireland situated in the south of Ireland. In Ancient Ireland, it was one of the fifths ruled by a "king of over-kings" . Following the Norman invasion of Ireland, the ancient kingdoms were shired into a number of counties for administrative and judicial purposes...

. Their origins are unclear but they may have been of fairly recent Gaulish

Gauls

The Gauls were a Celtic people living in Gaul, the region roughly corresponding to what is now France, Belgium, Switzerland and Northern Italy, from the Iron Age through the Roman period. They mostly spoke the Continental Celtic language called Gaulish....

 derivation. Some evidence exists for their having been active in Roman Britain

Roman Britain

Roman Britain was the part of the island of Great Britain controlled by the Roman Empire from AD 43 until ca. AD 410.The Romans referred to the imperial province as Britannia, which eventually comprised all of the island of Great Britain south of the fluid frontier with Caledonia...

.

Legendary figures belonging to the Deirgtine include Mug Nuadat

Mug Nuadat

In Irish mythological history Mug Nuadat was a legendary, supposed King of Munster in the 2nd century AD. He was, according to later medieval tradition, a rival of the High King, Conn of the Hundred Battles and for a time after the year 123 was the de facto ruler of the southern half of Ireland...

, Ailill Aulom

Ailill Aulom

In Irish traditional history Ailill Ollamh , son of Mug Nuadat, was a king of the southern half of Ireland. Sabia, daughter of Conn of the Hundred Battles, was his wife. He divided the kingdom between his sons Éogan, Cormac Cas, and Cian. Éogan founded the dynasty of the Eóganachta...

, Éogan Mór, and Fiachu Muillethan

Fiachu Muillethan

Fiachu Muillethan or Fiachu Fer Da Liach , son of Éogan Mór, was a legendary king belonging to the Deirgtine, the proto-historical ancestors of the Eóganachta dynasties of Munster...

. Though literary claims were later made that these early figures were rulers of Munster, their descendants did not in fact gain political supremacy over the established Dáirine

Dáirine

The Dáirine , later known dynastically as the Corcu Loígde, were the proto-historical rulers of Munster before the rise of the Eóganachta in the 7th century AD. They appear to have derived from the Darini of Ptolemy and to have been related to the Ulaid and Dál Riata of Ulster and Scotland...

 or Corcu Loígde

Corcu Loígde

The Corcu Loígde , meaning Gens of the Calf Goddess, also called the Síl Lugdach meic Itha, were a kingdom centered in West County Cork who descended from the proto-historical rulers of Munster, the Dáirine, of whom they were the principal royal sept...

 until the 7th century AD. Among the famous tales from which the Deirgtine are known is the Cath Maige Mucrama.

While kinship is not asserted, the Deirgtine are known to have had a close political relationship with the Déisi

Déisi

The Déisi were a class of peoples in ancient and medieval Ireland. The term is Old Irish, and derives from the word déis, meaning "vassal" or "subject"; in its original sense, it designated groups who were vassals or rent-payers to a landowner. Later, it became a proper name for certain septs and...

 of Munster, who may have been their most important early facilitators. The names of several figures from the Deirgtine (Eóganachta) pedigrees are found in ogham

Ogham

Ogham is an Early Medieval alphabet used primarily to write the Old Irish language, and occasionally the Brythonic language. Ogham is sometimes called the "Celtic Tree Alphabet", based on a High Medieval Bríatharogam tradition ascribing names of trees to the individual letters.There are roughly...

 inscriptions in the Déisi country of County Waterford

County Waterford

*Abbeyside, Affane, Aglish, Annestown, An Rinn, Ardmore*Ballinacourty, Ballinameela, Ballinamult, Ballinroad, Ballybeg, Ballybricken, Ballyduff Lower, Ballyduff Upper, Ballydurn, Ballygunner, Ballylaneen, Ballymacarbry, Ballymacart, Ballynaneashagh, Ballysaggart, Ballytruckle, Bilberry, Bunmahon,...

.

It is also the case that a number of figures, mythological and historical, later thought to belong to the Deirgtine and listed in the Eóganachta pedigrees did in fact belong to the Érainn, but were adopted as ancestors. The earliest reliable ancestor of the Eóganachta and actual founder of the dynasties is Conall Corc

Conall Corc

Corc mac Luigthig, also called Conall Corc, Corc of Cashel, and Corc mac Láire, is the hero of Irish language tales which form part of the origin legend of the Eóganachta, a group of kindreds which traced their descent from Conall Corc and took their name from his ancestor Éogan Mór. The early...

.