Tuathal reigned for thirty years, and is said to have fought no less than 133 battles with the Attacotti. He was at last slain himself by his successor, Nial, who, in his turn, was killed by Tuathal's son. Conn "of the Hundred Battles" is the next Irish monarch who claims more than a passing notice. His exploits are a famous theme with the bards, and a poem on his "Birth" forms part of the _Liber Flavus Fergusorum_, a MS. volume of the fifteenth century. His reign is also remarkable for the mention of five great roads[101] which were then discovered or completed. One of these highways, the Eiscir Riada, extended from the declivity on which Dublin Castle now stands, to the peninsula of Marey, at the head of Galway Bay. It divided Conn's half of Ireland from the half possessed by Eóghan Môr, with whom he lived in the usual state of internecine feud which characterized the reigns of this early period. One of the principal quarrels between these monarchs, was caused by a complaint which Eóghan made of the shipping arrangements in Dublin. Conn's half (the northern side) was preferred, and Eóghan demanded a fair division. They had to decide their claims at the battle of Magh Lena.[102] Eóghan was assisted by a Spanish chief, whose sister he had married. But the Iberian and his Celtic brother-in-law were both slain, and the mounds are still shown which cover their remains. Conn was succeeded by Conairé II., the father of the three Cairbrés, who were progenitors of important tribes. Cairbré Muse gave his name to six districts in Munster; the territory of Corcabaiscinn, in Clare, was named after Cairbré Bascain; and the Dalriada of Antrim were descended from Cairbré Riada. He is also mentioned by Bede under the name of Reuda,[103] as the leader of the Scots who came from Hibernia to Alba. Three centuries later, a fresh colony of Dalriadans laid the foundation of the Scottish monarchy under Fergus, the son of Erc. Mac Con was the next Ard-Righ or chief monarch of Ireland. He obtained the royal power after a battle at Magh Mucruimhé, near Athenry, where Art the Melancholy, son of Con of the Hundred Battles, and the seven sons of Oilioll Oluim, were slain.