From the description:
All people of Bostonia (and presumably of the entire world) are the children of a race of powerful wizards called Ancients. The Ancients were masters of elemental air, fire, water and earth as well as time and space. This power gave them an advanced magical "technology" that permitted the building of huge cities, flying machines, mystic gates and other wonders.
The setting document includes history, extensive geography, notable places, religion, and culture. The setting includes details on the races unique to Runebearer.
In addition to the World of Bostonia setting guide, Bostonia Genealogy Tables (6 pages) and Map of the Lands of Bostonia (1 page) are available as separate downloads.