This stunning book is set in a fantasy world based on the historical Byzantine Empire. It is actually amazing how many varied aspects of the Byzantine Empire are represented in his fictional Sarantine Empire. Some are obvious, such as a fallen empire to the west and competing factions supporting charioteers. Some are very obscure, such as a violent religious dispute that mirrors Christianity's Arian heresy. Unlike the historical empire, the Sarantine Empire is one in which alchemy, pagan gods, and the like are, at least sometimes, actually real.

Into this richly described world comes the protagonist, Caius Crispus, or Crispin for short. Crispin is a mosaicist in the barbarian kingdom that was once part of the now-fallen western empire. One day, an Imperial Courier arrives with a letter for Crispin's mentor Martinian, inviting the latter to Sarantium, the imperial capital, to work on a new chapel. Martinian, feeling too old for such a journey, invites Crispin to assume his name and travel in his stead.

Approximately half of the book discusses the journey to Sarantium. Due to the tardiness of the courier, Crispin misses the sailing season and must travel on foot. The journey is at times harrowing, but he successfully arrives in the city with a couple of companions he picks up along the way. Once he arrives in the capital, he is very rapidly drawn into various court intrigues, having to use his substantial wits to compensate for how far out of his element he is.

Of course there are several substantial subplots in this complex and detailed story as well. They all add up to a rich tapestry of a story that surpasses even Kay's previous novels.

While Sailing to Sarantium is the start of a duology, reaching the end of the first volume didn't leave me with the empty feeling I experience with so many series. Kay succeeds in concluding enough of the plot lines to leave the reader fulfilled but still wanting more. While the book does end with a somewhat clumsy teaser scene, this was one of the few times where I was glad I read the book when it became available rather than waiting for the series to be complete.