In 2E 852, allied Nord and Breton forces crossed the borders into Cyrodiil and occupied the major passes and settlements in the Jerall Mountains. Making their headquarters for the winter at Sancre Tor, the Nord-Breton allies dared King Cuhlecain's new general, Talos, to assault them in their mountain fortresses.
When they learned that General Talos had mustered an army in the dead of winter and was marching to assault Sancre Tor, they were elated. Sancre Tor was impregnable, its citadel on high cliffs overlooking the lower city, nestled in a high mountain basin with steep, unscalable cliffs in their rear.
The Cyrodilic army was small, poorly trained and outfitted, short on rations, and unprepared for winter campaigning. As their ragged units assembled in the lowlands beneath the citadel, the Nord-Breton allies confidently assumed that their enemy had delivered himself into their trap.
The citadel was not only protected by an unscalable cliff in front and unscalable heights in their rear, but the entrance to the citadel was magically concealed under the appearance of a large mountain lake in the basin beneath the heights. Accordingly, the Nord-Breton allies left on a small force to defend the citadel, descending through lower passages to attack and overwhelm the cold, hungry Cyrodilic forces before them. They expected to defeat, overrun, and annihilate General Talos' army, leaving no one to oppose their springtime descent into the Cyrodilic Heartlands.
Leaving a weak force in the lowlands to draw out the defenders, General Talos approached the citadel of Sancre Tor from the rear, descending the supposedly unscalable heights behind the citadel, and sneaking into the magically concealed entrance to the inner citadel. This remarkable feat is attributed to a Breton turncoat sorcerer, who revealed both the existence of an obscure mountain trail down the heights behind the citadel and the secret of the citadel entrance concealed beneath its illusory lake surface.
While the Cyrodilic army in the lowlands fought a desperate defense against the Nord-Breton sortie, General Talos and his men entered the citadel, swept aside the sparse defense, captured the Nord-Breton nobles and generals, and compelled them to surrender the citadel and their armies. The confused and demoralized Nord captives, deserted the alliance and swore loyalty to Tiber Septim. The High Rock generals were executed and the captive Bretons imprisoned or sold into slavery. At the end of the battle Sancre Tor was left as a ruin now occupied by Skeletons and spirits of fallen Blades