Arrows of the Sun (Avaryan Rising)

Judith Tarr returns to her created world of mages in this fourth volume of her Avaryan Rising series. The Sunborn's heirs have ruled the two empires for four generations, but the latest heir to the thrones of Endros and Asanion does not sit easily. Estarion saw his father die in the golden palace of Asanion, victim of mage-wrought poison and the enduring hatred of a conquered race. On the very day of his enthronement, after long years of regency, Estarion is forced to agree to return to Asanion - and he vows that even if he must rule that accursed land, he will never love it.
With the new Golden Emperor travels his beloved, Vanyi, the mage-born priestess who can never be Empress. She was born a common fisherman's daughter, but gifted with great power - more, perhaps, than the Emperor himself wields.
And waiting for them In the Golden Palace of Asanion is plot and intrigue, conspirators who would kill the son as they killed the father. They would place their own creature on the throne of empires, and their own God in the seat of the Sunlord.