Two major factors make up the Trilogy’s setting: the empire and the geography of the Seventh World itself.
The Seventh World’s geography is loosely based on that of our own world, as the story was originally written as a sort of alternate history — though that approach changed drastically as the Trilogy was written! Bryllan and the Green Isle correspond to Great Britain and Ireland (Cryneth is Wales; the Highlands, of course, are Scotland). Galce corresponds to France; the Eastern Lands to Eastern Europe; Italya to Italy/southern Europe; and the North to Scandinavia.
These areas with their dramatic histories inspired geographic features, place names, and even some story details. But the correspondence is loose. The Seventh World has very much become a place of its own.
The lands of the Seventh World are gathered under the rule of the Morel Dynasty, an empire which has been in place since Lucius Morel conquered the tribes five hundred years before Worlds Unseen began — leaving only the wandering Gypsies to remind people of the way things once were.
The Morel family has brought good to the Seventh World by bringing peace between its lands and peoples, but the empire also brings oppression and fear. It is the empire that constructs and runs the cruel Orphan Houses, and the empire’s High Police demand the service of young men from all over the Seventh World, tearing apart families and bringing ruin to the hearts of those who serve. The empire is antagonistic toward the Gypsies and sometimes persecutes them, and it levels heavy taxes on its people — especially in the Eastern Lands, where rebellion has long brewed.
In Worlds Unseen, the empire is under the rule of Lucien Morel. But lurking behind the scenes is the real key to the empire’s power and to its evil: the Order of the Spider, a mysterious group of black-cloaked figures who commune with the Blackness and wield terrible power.