The origins of this guild during the Hundred Kingdoms era are described in "Two to Conquer" as the merger between the Sisterhood of the Sword, a military-mercenary guild, and the Priestesses of Avarra, a cloistered order that offered medical and other care to women, primarily abused women. Towards the end of "Two to Conquer", Carlina di Asturien comes to believe that the two guilds need to work together for the benefit of all women on Darkover. Bradley acknowledged a Patricia Matthews fan story as the origin of the Sisterhood of the Sword, and described the Priesthood of Avarra as a counterforce.