The Pocket guide to the empire, 3rd Edition, states :
While the Emperor chose not to remarry following the Empress's death more than fifty years ago, she left to him three healthy boys, who have spent their advlt years learning the art of politics from their masterful liege and father.
This means that Caula Voria died before 3e383, which is a 6 years before the interregnum.
But we can read in The Black Horse Courier " EMPEROR AND HEIRS ASSASSINATED!" :
Emperor Uriel was finally rescued and restored and the impostor defeated by the agency of the sorceress Ria Silmane and her shadowy prot?g?, but the affairs of the empire were in great disorder, and Empress Caula Voria, exhausted by her ordeal, withdrew from public life.
which means she was still alive in 3e399.
Does anyone knows when she died ? Can we safely assume that there is a typo in the pocket guide, and that she died more than fitfteen years ago ?