11th July 703 AD: The Battle of Corann/Cath Corainn was fought on this day. The battle was a clash of arms between two of Ireland’s great kings - Cellach mac Rogallaig, king of Connacht (from the Uí Briúin dynasty) and Loingsech mac Óengusso, king of Tara and of the Cenél Conaill (a sub branch of the great Uí Néill dynasty.)
The events leading up to the battle began when Loingsech mac Óengusso, king of Tara, invaded Connacht with a large host intending to give battle of Cellach mac Rogallaig, the king of the province. As his army advanced, Loingsech’s poets satirized Cellach, making fun of his old age and his inability to cope with the king of Tara.
Legend has that when Cellach saw the devastation wrought by Loingsech, he summoned the two Dúnchads (i.e. Dúnchad Muirisce and another man named Dúnchad), whom he had chosen to succeed him as king of Connacht. With the one Dúnchad on his right and the other on his left, Cellach harangued the Connacht forces, telling them to defend their freedom bravely. Then, Cellach led his troops into battle. The Uí Néills were routed and Loingsech was killed along with a number of those closest to him, including three of his sons.
The site of the battle is not known with certainty, but the old name Corann refers to parts of what is now Co. Sligo and Co. Mayo.
The battle of Corann in which fell the king of Ireland, Loingsech son of Aengus son of Domnall son of Aed son of Ainmire, i.e. by Cellach of Loch Cime son of Ragallach, together with his three sons, and two sons of Colgu, and Dub Díberg son of Dúngal and Fergus Forcraid and Congal of Gabar, and many other leaders. On Saturday, the fourth of the Ides of July, at the sixth hour, this battle was fought.
Annals of Ulster 703.2