During his reign Olion had a series of catacombs constructed beneath Centauri Prime's capital city that lead out to the outlying regions to serve as a means of escape. According to legend, Olion was absolutely paranoid that his people might turn against him. The only person aside from Olion who knew the layout of the maze was the catacomb's architect whom the Emperor had assassinated to keep the secret.
- Across Time and Space: The Chronologies of Babylon 5 - cites the period as conjecture
- Out of the Darkness - the catacombs were built "centuries ago"