Tuathal Teachtmhar or Techtmar was a legendary High King of Ireland, reputed to have ruled in the 1st or 2nd century. His name derives from Celtic *Teuto-valos ("leader of the tribe, people") and his epithet may mean "great crossing", "great possession", or "legitimate". He was the ancestor, through his grandson Conn of the Hundred Battles, of the Uí Néill and Connachta dynasties.
Tuathal was the son of a former High King deposed by an uprising of "subject peoples" who returned at the head of an army to reclaim his father's throne.
The oldest source for Tuathal's story, a 9th century poem by Mael Mura of Othain, says that his father, Fiacha Finnfolaidh, was overthrown by the four provincial kings, Éllim of Ulster, Sanb (son of Cet mac Mágach) of Connacht, Foirbre of Munster and Eochaid Ainchenn of Leinster, and that it was Éllim who took the High Kingship. During his rule Ireland suffered famine as God punished this rejection of legitimate kingship. Tuathal, aided by the brothers Fiacha Cassán and Findmall and their 600 men, marched on Tara and defeated Éllim in battle at the hill of Achall. He then won battles against the Ligmuini, the Gailióin, the Fir Bolg, the Fir Domnann, the Ulaid, the Muma, the Fir Ól nÉcmacht and the Érainn, and assembled the Irish nobility at Tara to make them swear allegiance to him and his descendants. Later versions of the story suppress the involvement of the provincial nobility in the revolt, making the "subject peoples" the peasants of Ireland.
The Book of Invasions adds the detail of Tuathal's exile. His mother, Eithne, daughter of the king of Alba (originally meaning Britain, later Scotland), was pregnant when Fiacha was overthrown, and fled to her homeland where she gave birth to Tuathal. Twenty years later Tuathal and his mother returned to Ireland, joined up with Fiacha Cassán and Findmall, and marched on Tara to take the kingship.
The Annals of the Four Masters also mentions a similar revolt a few generations earlier, led by Cairbre Cinnchait, in the year of the death of the High King Crimthann Nia Náir, although his death appears to be unrelated to Cairbre's revolt. On this occasion Crimthann's son Feradach Finnfechtnach is the future king who escaped in his mother's womb, although the Annals claim he returned to reclaim his throne only five years later. The Annals regularly attempt to turn legend into history, but here the attempt is clumsy and unconvincing.
Seathrún Céitinn harmonises the two revolts into one. He has Crimthann hand the throne directly to his son, Feradach, and makes Cairbre Cinnchait, whose ancestry he traces to the Fir Bolg, the leader of the revolt that overthrew Fiacha, killing him at a feast. Cairbre rules for five years, dies of plague and is succeeded by Éllim.
After Éllim had ruled for twenty years, the twenty or twenty-five year old Tuathal was prevailed upon to return. He landed with his forces at Inber Domnainn (Malahide Bay). Joining up with Fiacha Cassán and Findmall and their marauders, he marched on Tara where he was declared king. Éllim gave battle at the hill of Achall near Tara, but was defeated and killed.
Tuathal fought 25 battles against Ulster, 25 against Leinster, 25 against Connacht and 35 against Munster. The whole country subdued, he convened a conference at Tara, where he established laws and annexed territory from each of the four provinces to create the central province of Míde (Meath) around Tara as the High King's territory. He built four fortresses in Meath: Tlachtga, where the druids sacrificed on the eve of Samhain, on land taken from Munster; Uisneach, where the festival of Beltaine was celebrated, on land from Connacht; Tailtiu, where Lughnasadh was celebrated, on land from Ulster; and Tara, on land from Leinster.
He went on to make war on Leinster, burning the stronghold of Aillen (Knockaulin) and imposing the bórama, a heavy tribute of cattle, on the province. One story says this was because the king of Leinster, Eochaid Ainchenn, had married Tuathal's daughter Dairine, but told Tuathal she had died and so was given his other daughter, Fithir. When Fithir discovered Dairine was still alive she died of shame, and when Dairine saw Fithir dead she died of grief.
Tuathal, or his wife Baine, is reputed to have built Ráth Mór, an Iron Age hillfort in the earthwork complex at Clogher, County Tyrone. He died in battle against Mal, king of Ulster, at Mag Line (Moylinny near Larne, County Antrim). His son, Fedlimid Rechtmar, later avenged him.
The Annals of the Four Masters gives the date of Tuathal's exile as 56 AD, his return as 76 and his death as 106. Seathrún Céitinn's Foras Feasa ar Érinn broadly agrees, dating his exile to 55, his return to 80 and his death to 100. The Book of Invasions places him a little later, synchronising his exile to the reign of the Roman emperor Domitian (81-96), his return early in the reign of Hadrian (122-138) and his death in the reign of Antoninus Pius (138-161).
(Wikipedia)