The Túatha Dé came with a great fleet to Ireland to take it by force from the Fir Bolg. Upon reaching the territory of Corcu Belgatan (which is Conmaicne Mara today), they at once burned their boats so that they would not think of fleeing to them. The smoke and the mist which came from the ships filled the land and the air which was near them. For that reason it has been thought that they arrived in clouds of mist.