The Battle of Nine Broken Skulls was an engagement between an undead army sent by Tar-Baphon against the orcs of Belkzen that was fought in 4719 AR in a muddy riverbed before the great city of Urgir. The orcish forces were lead by Ardax the White-Hair, ruler of Urgir, who had quickly gathered a loose collection of orc tribes to fend off the attackers. The battle ended in the defeat of Tar-Baphon's army.
After Tar-Baphon escaped from his prison of Gallowspire in 4719 AR, he sent several emmisaries to the orcs of Belkzen in an attempt to bring them under his control, just as he had in 3203 AR when he first rose as the Whispering Tyrant. Instead of uniting behind the lich, as they had done over 1700 years before, the orcs, under the leadership of Ardax the White-Hair, instead decided that they didn't want to die for the lich-king. They slaughered the envoys as soon as they had finished presenting their proposals, and mounted their heads on Urgir's walls. Their horses were sent back over the border to the Gravelands, dragging the decapitaded bodies behind them and with the lich's propasals stuffed into their necks.
This defiance angered Tar-Baphon greatly, and he sent an army of his undead to Urgir to teach the orcs a lesson, excpecting that the tribes would bicker with one another and fail to mount a successful defense. Instead, Ardax White-Hair hastily assembled a desperate coalition who successfully fought off the attackers at the Battle of Nine Broken Skulls. After Tar-Baphon's forces had been routed, Ardax strolled across the battlefield and picked out ten fallen undead skulls. Before the assembled mass or orcs, he held nine of them aloft, and named one of the undead they had defeated before crushing them with his bare hands. The tenth skull he named Tar-Baphon and adorned it with cow horns to mock the tyrant.
Instead of breaking the will of the orcs, as Tar-Baphon had intended, the battle instead showed them how powerful they could be if they were unified. The battle cemented Ardax as a great orc war leader, and the remaining orc chieftains declared him overlord soon thereafter.