It was fought between Muircheatach O'Brien, the King of Thomond, and Richard De-Clare, an Anglo-Norman Lord.
The Battle was part of the Bruce Wars which took place over the course of 3 years in Ireland and were sparked by the arrival of Prince Edward Bruce, who was brother to King Robert of Scotland.
When Richard De Clare heard of his allies' defeat at Corcomruadh, he retaliated by leading the attack on Thomond, which until then had been respected by the English forces as a sovereign state.Though De Clare's approach was well thought out and tactical, he found that his forces could not defeat the Irish on their home ground. He himself was killed, along with over 80 noble Englishmen.
The defeat of the invading forces at the Battle of Dysert O'Dea meant that it would be another 200 years before the Kingdom of Thomond would fall under foreign control.