Vineart war trilogy

Once, all power in the Vin Lands was held by the prince-mages, who alone could craft spellwines, and selfishly used them to increase their own wealth and influence. But their abuse of power caused a demigod to break the Vine, shattering the power of the mages. Now, fourteen centrueis later, it is the humble Vinearts who hold the secret of crafting spells from wines, the source of magic, and they are prohibited from holding power. But now rumors come...

An island nation has vanished. Men of honor and magic have died unnatural deaths. Slaves flee in terror. . . . Are the silent gods beginning to speak? Or is another force at work in the Lands Vin? Jerzy, Vineart apprentice and former slave, was sent by his master to investigate strange happenings--and found himself the target of betrayal. Now he must set out on his own journey, to find the source of the foul taint that threatens to destroy everything...