In 40PC Arch Lector Gottlieb I announced that he had received a prophetic vision from Sigmar. In the dream he claimed to have seen a twin-tailed comet crashing into a tall mountain, far to the south of Sigmarheim. The mountain then erupted, smoke and ash rising to form a rune of evil origins.
Seeing this as a sign to reach the mountain Gottlieb petitioned Emperor Otto II to allow him resources and men to travel south and destroy the evil that lurked in the ashen peaks. Otto, glad to be rid of the troublesome religious influence in the Empire, was eager to send the priest on his way, though he was loathe to provide Gottlieb with any troops from his own standing army.
A force of several thousand was led south by Gottlieb, on an arduous journey that took over year. Despite small skirmishes against wild beastmen and goblins the crusade reached Boiling Peak and Gottlieb identified it as the mountain from his vision.
In a narrow valley the crusade was attacked by a large force of Skaven, the evil that lay at the heart of Boiling Peak. In a fierce battle both forces struggled to manoeuvre their infantry around giant blocks of basalt and dangerous vents of scolding gas. Still pre-prepared artillery positions made good use of the cramped terrain to destroy the blocks of Skaven infantry.
Spurred on by the fiery rhetoric of the warrior priests leading the crusade, knights from the Order of the Flaming Brand crashed through the centre of the enemy lines, smashing Skaven constructs and scattering rat-men. Meanwhile crazed flaggellants crashed through the rats and Gottlieb called upon the power of Sigmar to protect his army from dark magics.
The Skaven were all but destroyed by the crusade's assault, though the crusade had suffered heavy casualties itself. Still Gottlieb was satisfied with doing Sigmar's work. After placing warning runes around the Boiling Peak he ordered the crusade home. Barely 1 in 10 of the original crusade made it back to Sigmarheim but Gottlieb Rat-Slayer was rightly hailed and the power of the church had never been stronger.
To celebrate the victory Gottlieb I was permitted to expand the first church of Sigmar, building a new east wing and renaming the building the Cathedral of Sigmar in 44PC. By 45PC the population of the Empire had risen to 500,000 and the Nimarn valley settled ever further south, with the region of Kirchen tamed from the wild for the first time.