The First War for Armageddon was fought in 444.M41, when the Daemon Prince Angron united all the World Eater warbands under his banner and invaded the planet to butcher its populace for the greater glory of Khorne. The Space Wolves, Grey Knights, Armageddon Steel Legion and the planetary defence forces eventually repelled the invasion.
After which a nubbin Inquisitor decided to have all the mortals involved (ie, everyone except the Grey Knights and Space Wolves) force-laboured to death so the planet could be repopulated with new colonists who had not been exposed to chaos. You could say that the Space Wolves didnt think too much of that plan, and set about saving as many people as they could, and told the Inquisitor that he could take a long walk out of a short airlock. Said inquisitor thought that no one could defy the Inquisition, and decided the best thing to do was double down and call their bluff... against the Space Wolves
. Which resulted in a naval standoff where the inquisition was forced to run like little bitches.
They spend the next while scattering the survivors as far and wide as they could, while engaging in a running not-so-cold-war with the Inquisitor's Company of Grey Knights, who were so disgusted with what they were doing that they called it the Months Of Shame. Since his grand plan to bring the Space Wolves to heel wasnt working. The Inquisitor came up with a new plan; Attack The Fang
. The most unassailable fortress in the Imperium outside The Emperor's Palace on Terra.
Which went about how youd expect (rather poorly for the attackers).... and then
the whole rest of the Space Wolves showed up, the Entire chapter, because you do not
mess with Fenris. In desperation, the Inquisitor had a face-to-steel plate conversation with Bjorn The Fell Handed (because they woke his venerable ass up for this), hoping to talk some 'sense' into them, with the gracious offer of letting them surrender and take up a penitent crusade as punishment for their defiance. Naturally Bjorn told him where he could shove that.
It ended when Logan Grimnar, clad in Terminator armour, teleported into the Inquisition's flagship, charged
right across the bridge, vaulted onto the command deck and cut the Inquisitor's head off. Only Bjorn kept them from annihilating the entire force, and in the end, the Inquisition decided to let sleeping wolves lay.