David Drake is among my favorite authors, so I was quite excited when this book arrived. The Legions of Fire 
The story begins in Carce, capitol city of an empire that dominates the known world. Corylus, a soldier's son with a scholarly bent who grew up on the empire's frontiers, attends a public recital given by his friend Varus, a young aristocrat and scholar with aspirations of being a poet. Varus is reading his poem when he, Corylus, and Varus' sister Alphena are seized by bizarre visions, and Varus shocks the crowd- and himself- when he stops reading his poem, tears the manuscript apart, and begins making apocalyptic pronouncements warning of the imminent destruction of the world by fire. Pandareus, Varus and Corylus’ rhetoric instructor, takes the two young friends to meet his friend Priscus, one of the commissioners of the Sybilline Books- ancient prophecies that only a few men have ever seen, kept under strict guard and opened only by order of the Senate of Carce. During the meeting, Varus falls into another trance, and a startled Priscus reveals that Varus’ rants are in fact quotes from the Books.
Terrible supernatural forces are gathering around Varus' family and friends. Varus' father Saxa has been spending most of his time with a strange man named Nemastes, who claims to be a sorcerer from Hyperborea. Alphena, visiting the temple of Tellus with her and Varus' stepmother Hedia (who is not much older than they are) to pray for a suitable husband, is terrorized when the statue of the goddess moves and speaks in a man's voice, proclaiming that she will marry Spurius Cassius- a famous citizen of Carce put to death by the Senate centuries ago. Corylus finds himself repeatedly slipping over the boundary into some other world, where strange beings urge him to kill his friend Varus before it's too late. The cataclysm spoken of in the Sybilline Books that Varus has unwillingly prophesied is real, and its architects intend to use Varus as their instrument to bring it about. The barriers between worlds are weakening, and Varus, Corylus, Alphena, and Hedia all find themselves drawn into strange realms nothing like the world they know, where they must struggle to survive and find out how they can stop what is coming. If they fail, the entire world will burn.
I greatly enjoyed this book. Drake once again demonstrates his talent for intense action and complex plotting, juggling four major plot threads and viewpoint characters as their stories separate and then intersect again. Drake's use of historical and mythological inspirations is very effective, and he creates a world that feels very concrete and real and yet profoundly strange at the same time.
I liked the characters- the hedonistic yet grim-minded and duty-bound Hedia, earnest and straightforward Corylus, intellectual yet sentimental Varus, and fearful but determined Alphena. With Alphena and Varus, Drake also does a nice job of portraying courage and determination shown by people who are in completely over their heads, each in their own way, and know it but still press on. Drake has a knack for infusing the mindset of his viewpoint characters into the way each section is written without hitting the reader over the head with it, and makes each plot thread feel like its main character.
The setting is a little unusual. The Legions of Fire is not historical fantasy, but the story is set, sort of, in the early Roman Principate during the reign of Emperor Tiberius; for most practical purposes, Carce is Rome. Aside from Carce itself, even the names are kept the same: there are references to the Gauls and Carthaginians, real historical (to the characters as well as the reader) figures like Julius Caesar and Spurius Cassius, the Rhine and Danube rivers, and so on. I found this a bit jarring at first, but quickly came to like it. It allows Drake- who was a classics major in college and has frequently used his extensive knowledge of Latin literature and Classical history as inspirations- to set his story in a world that feels very solid and defined without the need for large digressions providing background information, and ancient Rome offers a setting that feels as alien as any fantasy culture. In my case, it helped that Classical antiquity is a longstanding interest of mine, but I think the setting will be enjoyable even for people who don't have that background.
The fantasy elements, too, are in large part grounded in real Roman (and Norse) beliefs, such as the prophetic Sibyline Books that are consulted by the Senate in times of crisis. Magic in Carce is likewise based on old Roman beliefs: It is secretive, feared, widely disapproved of both legally and socially and yet widely sought, and people who claim to wield it are more likely to be charlatans and con men than authentic magicians. Genuine magic in Carce's world is rare, sinister, and frequently unsavory and disturbing. Other aspects of the story draw on Norse myths. Again, you'll get more out of this aspect if you know something about the source material, but even without that background knowledge it's quite evocative and effective on its own.
I'd recommend The Legions of Fire
