The Price of Eyes - Janet Mcgiffin

In the final book, Irini returns to the throne. She tricks Constantine into divorcing Maria and exiles her and Constantine’s two daughters to Abbess Thekla’s island convent where Maria goes mad. Irini misleads Constantine into taking revenge on the soldiers who arrested her and the empire erupts into civil war, army against army, Irini against Constantine. Fearing for her life, Irini traps Constantine, wounding his eyes, but Thekla rescues him. Irini is finally empress in her own right. But will Thekla help her hold the throne?