About five hundred years before the Reckoning struck the planet Enroth, the mage Verhoffin declared that his tower was a sovereign province, and independent of the great Ursanian Empire. When Emperor Trandis tried to have him assassinated, Verhoffin cast a spell that laid waste to half the Empire. The event caused the Empire to dissolve, and formed the basis for the new way of measuring time: in the same way that Enroth spoke of the number of years AS (After the Silence), Axeoth spoke of the number of years AC (After the Cataclysm).
From the manual Edit
Before 0 BC, Rysh, the continent Chedian lies upon, was a very different place. The Ursanian Empire’s hold on the continent was nearly complete. Their area of influence was large, and their ambitions larger. During this period in the Ursanian Empire, its emperors were plagued by suspicion and mistrust. Immediately prior to 200 BC, in a remote province near the centre of the Ursanian Empire, a previously unknown sorcerer appeared and constructed a large tower. He used the name Verhoffin, and claimed the tower as a sovereign province independent of the Ursanian Empire. Emperor Ralfor and his successors mounted several unsuccessful campaigns against Verhoffin.
Somewhere near 10 BC, Emperor Trandis assigned an assassin named Nazrim to assassinate Verhoffin. After 10 years and the commissioning of several magical artifacts, Nazrim attempted to end Verhoffin’s life. Nazrim failed, and in response to this attempt, Verhoffin climbed to the top of his tower and cast a spell that laid waste to half the Ursanian Empire. For thousands of miles, he wreaked havoc and destroyed land. Earthquakes ripped the surviving cities apart. A giant section of the land surrounding Verhoffin’s Tower was torn asunder, forming what is now known as the Verhoffin Sea. Most of the citizens of the Ursanian Empire were left without homes or families. Although the Ursanian Empire would last another 13 years, this event is generally associated with the fall of the Ursanian Empire.