Broken Vows (Daniells, Cory. Last T'en Trilogy, Bk. 1.)

It has been six hundred years since Imoshen the First, Causare of the T’En, brought her beleaguered people across the seas to Fair Isle. The magical folk mixed with the natives, bringing culture and sophistication, and made the island one of the wealthiest, most powerful nations in the known world. In one night, all is lost. Imoshen, namesake of the first Empress, is the last pure-blooded T'En woman, left behind when her kinfolk went to die in defence of their homeland. The savage Ghebites, barbarians from the warm north, have conquered Fair Isle, and their general, Tulkhan, claims her as his right of conquest. Proud and fierce, trained in arts of war and possessed of extraordinary healing gifts, Imoshen must choose to submit to the barbarian soldier and save her people's heritage... or to die in a futile gesture of defiance.