Where does Journey of Souls take place?
Around the year 1200, France was divided among numerous warring nobles, several of them English. Richard I of England, the Lionheart, ruled Aquitaine until he died in 1199.
The events in Journey of Souls take place in the County of Toulouse, (the area in light purple), mostly under the control of Raymond VI, Comte of Toulouse and his vassals.
The coastal section of the County of Toulouse corresponds approximately to the modern-day region of France called Occitanie. Tour operators often refer to this region as "Cathar Country".
Large parts of the County of Toulouse were controlled by Raymond Roger, Viscomte of Carcassonne (and Beziers and other cities), and the Comte of Foix. These holdings were divided among their vassals, and so on.
The border between Foix and Carcassonne on the north, and Navarre and Aragon on the South, corresponds to the Pyrenees. Alliances with Aragon with common.
Northern parts of France had a feudal system that matches most people's ideas. Bonds of fealty were strong and ownership of holdings was well defined. Primogeniture was practiced (that is, all of a family's holdings went to the oldest son). In southern France, holdings were often divided among several heirs. This meant that holdings became smaller over time. Bonds of fealty in the south were weaker and alliances often shifted. This political disorganization made the south vulnerable to invasion.
In 1209 the Crusaders invaded from the east, primarily capturing the walled cities in the plains controlled by Trencavel. In later years they attacked Toulouse and Foix and beseiged the mountain strongholds.
The imaginary walled city of Mirefoix in my novel is near Foix, in the foothills of the Pyrenees.