The Achturardackians were pioneers of sigil based magic, and their techniques for building glyphs, sigils and seals remain the foundation of magic inscription.
The relic of an old Sorcerer, the Glyph of Tarnos Krae is a window into the past.
The ruling family depends on some magical artifact or place to secure their right to rule. A monarch isn't considered legitimate until he or she has been "accepted" by the artifact or place, whatever that might entail. It is also possible that some one else, not of the ruling family, could be accepted as the legitimate heir... A fact which the monarchs would like to keep secret.