The new galaxy to which the pilgrims from Old Earth traveled in their Arks. The name was agreed upon as to show no favoritism to any specific nationality from Old Earth. Also because of the 13 main planets inhabiting it.
In Greek Mythology Mt. Olympus was regarded as the “home” of the Twelve Olympian gods of the ancient Greek world. It formed itself after the gods defeated the Titans in the Titan War, and soon the palace was inhabited by the gods. It is the setting of many Greek mythical stories.
The thirteen planets in Olympus were named after the Twelve Olympian Gods plus Hades, and the moons of each planet named based on the planets name.