Star Sanctum was once maybe the greatest monument erected to the goddess of magic, Mystra; Large temple complex, that housed not only great statues of Mystra and her exarchs, but also one of the largest libraries dedicated to magical knowledge that humans had built. Now, all that is left for it are ruins and ash, as it's home town Jiddab stands deserted, ruined and empty.
Pilgrims still wander to the ruins, attempting to connect with the goddess, and trying to recover the lost knowledge under the rubble.
The Sanctum was build to honor the Mother of all Magic and the knowledge that mortals had discovered in her name. Altars, libraries, reading rooms, study spaces, halls for debate and learning - Star Sanctum grew to be a great place for pilgrims and those eager to learn and understand magic and The Weave.
However, during a power dispute of sons of the Sultan, group of soldiers attacked Jiddab. Why instructed to avoid the Sanctum, greediness of the soldier made them cause harm to the sacred halls. According to stories, divine entity let the soldiers feel the wrath of the goddess whose temple they had defiled, and fire rained from the sky, destroying the town and Sanctum with it as a punishment of their insolence.