The Saga of the Renunciates.

In the three novels which comprise THE SAGA OF THE RENUNCIATES, Marion Zimmer Bradley tells the masterful tale of two valiant women who face and try to break the invisible chains of custom, convention, habit and expectation with which society binds women, and women bind themselves.
Magdalen Lorne is a Terran woman born and reared on Darkover. She thinks herself the perfect Terran undercover Intelligence agent, and disguises herself as a Free Amazon to enable her to fulfill a mission to free a Terran man from kidnappers. But when she herself is captured by a band of real Renunciates, she discovers they have a harsh punishment for any pretenders: she must swear the Oath of the Free Amazons, relinquish her former life, and become a Renunciate in reality.
Jaelle has been raised in the harsh patriarchal environment of the Dry Towns. Her mother Mellora is a Comyn woman who has been kidnapped in order to breed laran-gifted offspring for her barbarian "husband." But when a...