It was built by Emperor Sudkahanchoza to help the magicians fend off The Stranger. Since then, it was the place where people with magical ability was taken to undergo training. During training, he would be separated by his family and possessions. Of every five persons inducted into training to become a Great One, only one (on an average) makes it to this ultimate goal, and takes his or her place in the Assembly of Magicians, while those who fail, die in the process.
The Magicians' community at Stardock was modelled after the City of Magicians