The 4th edition "Sanctuary of Ice" sourcebook presented the intriguing situation of the Covenant of Tarragon Vale, whose members vanished one day, leaving a group of magi claiming to be the hightful owners of both the covenant and its growing fortune of vis.
And what about in your campaigns? What impact did the Tarragon Vale or the Heirs of Tarragon Vale had in your campaigns? What caused the Vanishing? And was it ever found out? What impact did the Heirs ever had? What were their Houses, how many were they, and where did they live while waiting to claim their inheritance?