Sorte is the hereditary sorcery of the Vodacce nobility.  Unlike its Montainge couterpart of Porte, Sorte is only inhereted and accessable by women.   It is Fate Magic, the ability to see the strands of fate the link the living to each other and the power to pull on those strands.  This allows for some prophetic insight and vision of the future, as well as altering likelihood of immediate events, bestowing blessings and curses, and seeing the true nature or Arcana of others.  Physically pulling someone by their strands is also an application of this sorcery, as is following a thread to track down the individual it is tied too.