Children of earth and sky (2016)

"The bestselling author of the groundbreaking novels Under Heaven and River of Stars, Guy Gavriel Kay is back with a new novel, Children of Earth and Sky, set in a world inspired by the conflicts and dramas of Renaissance Europe. Against this tumultuous backdrop the lives of men and women unfold on the borderlands--where empires and faiths collide. From the small coastal town of Senjan, notorious for its pirates, a young woman sets out to find vengeance for her lost family. That same spring, from the wealthy city-state of Seressa, famous for its canals and lagoon, come two very different people: a young artist traveling to the dangerous east to paint the grand khalif at his request--and possibly to do more--and a fiercely intelligent, angry woman posing as a doctor's wife but sent by Seressa as a spy. The trading ship that carries them is commanded by the accomplished younger son of a merchant family, ambivalent about the life he's been born to live. And farther east a boy trains to become a soldier in the elite infantry of the khalif--to win glory in the war everyone knows is coming. As these lives entwine, their fates--and those of many others--will hang in the balance when the khalif sends out his massive army to take the great fortress that is the gateway to the western world..."--