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Though Karrn failed in his conquest, his wars helped raise awareness of the dragonmarked as his soldiers traveled to distant lands. Over the next few centuries, the families began to communicate with one another, with the leaders of Sivis and Cannith taking the greatest initiative. However, it would take a second war to truly bring the families together and forge the foundation of the modern system of houses.
In the present day, few truths survive from the War of the Mark. History is written by the victors, and the dragonmarked houses have had fifteen hundred years to codify the persecution of the aberrants. What remain are superstitions and folktales: myths of aberrant monsters whose power could shatter cities. Many aberrants were said to be driven mad by the power of their marks—children of Khyber, touched by darkness. Those who bore the true marks were champions blessed by Siberys, or so the dragonmarked claimed. All that is truly known is that the aberrant dragonmarks of old were not bound by bloodline, and that they were as unpredictable as they were powerful.
Some say the fledgling dragonmarked houses saw a purge of the aberrants as the means to ensure their mystical monopoly. Others believe that the threat of the aberrants was inflated to force the dragonmarked families together. A few sages have suggested that the entire war and its aftermath were the work of the dragons of Argonnessen: that the creation of the houses served the Prophecy, and that the dragonmarked have always been unwitting tools of these ancient wyrms.
Some of the heroes and events of the War of the Mark are discussed in Chapter 4 and in the Sharn: City of Towers supplement. Alliances were forged in the heat of battle, and in the aftermath of the conflict, the leaders of the young houses formed the council of the Twelve. This arcane cabal established the unifying traditions of the dragonmarked, and set the standards by which the houses are governed to this day.
Source: Dragonmarked