Cleritors and Magnators might remember that there was a group of Vale Artists called Portors and that some were martyred with many other rebels, but they would be unlikely to attack significance to it - under the Umbrian Protectorate, there were more than 20 spires in this Vale alone, and close contact with the two Vales further east, who had an additional 30 or so. Almost all those lost, abandoned, ruined, or Eaten Spires had their own Vale Art - so one more lost school of technique does not stand out, even if you do not recall which Spire it belonged to