Conn Céad Cathach
Ir.: "Champion of a Hundred Battles"
ca. 110 - 157 CE
Irish Pseudohistorical King
Ard Rí (high king) of Ireland, he was the son of Fedhlimidh Rachtmar, the high king, and Ughna, daughter of the king of Lochlinn1. Between the kingship of he and his father, Conaire Mor ruled Ireland. Conn challenged Conaire to battle, defeating Conaire in Meath.
Supposedly, at Conn's birth, five roads to Temhair were discovered, which had never been noticed before: Slighe Asail, Alighe Miodhluchra, Slíghe Cualann, Slighe Mór, and Slighe Dála. Slighe Mór later became the dividing line between Leath Chuinn and Leath Mhogha (see below).
For most of his reign, Conn was at war with one king or another. In particular, his war with Eoghan Mór2--also called Mogh Nuadath--led to the partition of Ireland into half. The origin of their feud is in the earliest Irish pseudohistory, with the feud between the brothers Eber and Eremon, the two sons of Mil Espaine--in other words, the original Milesians who came to Ireland.3 Conn was descended of Eremon, while Mogh Nuadath was descended of Eber. When Mogh Nuadath realized that Conn, as a descendant of Eremon, had gained dominion over him, he rebelled. At the battle of Magh Lena, the two kings divided Ireland into two sections: Leath Mhogha and Leath Chuinn, or, "Mogh's Half" and "Conn's Half." This division lasted up through the age of Brian Bórúmha (ca. 1000 CE).
There are some legends that say Conn had a hand in the settling of Dalriada in Scotland.
Conn was killed at Temhair in 157 CE when the king of Ulster sent fifty warriors disguised as women to kill him. This enmity between Connacht and Ulster, of course, is reminiscent of the Ulster Cycle, and the enmity between Medb and Conchobhor mac Nessa.
The most famous story associated with Conn is that of Baile in Scaíl, "The Phantom's Frenzy." In this tale, Conn and his men suddenly find themselves in a fairy mist, and are lead to the house of Lugh Lamhfada. Here, Conn is given the cup of sovereignty and is told how many of his decendants will rule Ireland. The story is simliar to the grail quest, with Conn as Perceval, Lugh as the Fisher King, and the cup of sovereignty as the Holy Grail.
The most famous of Conn's sons are Connla and Art mac Cuinn. Of Connla, it is said that a fairy woman fell in love with him, and the two left for Tir na nÓg. Connla was never seen again, and so his brother Art was called Art Óenfher--"The Lone One."4 Other stories, though, say that Connla was killed by his uncles in a power-grab.
As for Art, he seized the throne of Ireland, becoming ard rí. His son was Cormac mac Airt, who, unlike his reputed ancestors Art and Conn, may have actually existed.
Keating, Geoffrey. The History of Ireland. ca. 1350? Found at CELT: The Corpus of Electronic Texts: http://www.ucc.ie/celt/published/T100054/index.html.
The Annals of the Four Masters. A six-volume work of the 16th century (IIRC). It can now be found at CELT: The Corpus of Electronic Texts: http://www.ucc.ie/celt/published/G100005A/index.html
"Baile in Scaíl." The Encyclopedia of Celtic Wisdom. ed. Caitlin and John Matthews.
Ancient Irish Tales. ed. T. Cross & H. Slover. Barnes and Noble, 1995 (reprint).
1. Lochlinn: presumably Scandanavia, though some scholars narrow this down to Denmark. Probably due to the Viking raids, the Scandanavians--under the guise of the people of Lochlinn--often figure in the pseudohistorical Irish and Welsh tales, as they were written in the Viking and post-Viking age of conquests. It is unknown if they would have been as prominent in the original, oral tales; if anything, Lochlinn often stands in as the typical "far away place" that, say, Sarras would play in the medieval romances.
2. Eoghan Mór: eponymous founder of the Eoghannacht clan.
3. Eber and Eremon: the theme of warring brothers who found a nation or are the origin of civilization is common in western culture; compare to Romulus and Remus, or Cain and Able.
4. This type of story is reflected in "The Colloquy of the Old Men" in which we are told of how Oisín went off with a fairy woman; and in the story of "The Voyage of Bran" in which Bran sails to Tír inna m-Ban, the Land of Women.