The Battle of Dragon Wall was a major conflict that occurred during the course of the Nordic-Orc War. It was fought between the Orcs of Orsinium, aided by Mauloch, and the Nords of Skyrim. Not much is known about the battle proper. At some point, the Nords succeeded in overcoming the Orcs and their defenses. The Nordic chieftain, whose name has descended into myth and legend, who dueled with Mauloch, but at a cost for the chieftain was struck down by retreating Orcs. The final fate of the Orcish survivors is unknown. What is known is that Mauloch headed east after his defeat in this battle, and his rage filled the sky. This year would later become known as "The Year of Winter in Summer" 
At the time of this battle, the Nords were engaged with the Dunmer of Morrowind, and also the petty kingdoms of Cyrodiil. It is unknown how the loss of so many men affected those battles.