Battle of Lough Raska

Two armies of nine thousand men each collided near Corcomroe Abbey in 1317, splitting the O'Brien kindred into rival factions. Diarmait O'Brien drove Donnchadh O'Brien from the field, securing Murtagh's claim and setting the stage for later wars. The lough water likely drank red that day, while men from both sides bled into the same Clare grass.