Sailing to Sarantium, Paperback/Guy Gavriel Kay

From the renowned author of Lord of Emperors , Children of Earth and Sky , and Tigana Crispin is a master mosaicist, creating beautiful art with colored stones and glass. Summoned to Sarantium by imperial request, he bears a Queen's secret mission, and a talisman from an alchemist. Once in the fabled city, with its taverns and gilded sanctuaries, chariot races and palaces, intrigues and violence, Crispin must find his own source of power in order to survive-and unexpectedly discovers it high on the scaffolding of his own greatest creation.