Soldier of the Mist

Soldier of the Mist is a Historical Fantasy novel by Gene Wolfe. A prologue claims the story is the translated version of an ancient scroll written (mostly) by a man called Latro, a Roman mercenary trapped in Ancient Greece after the defeat of Xerxes's Persian army at the Battle of Platea. In the battle, Latro suffered a nasty head wound, which now causes him to forget everything from the day before. However, he can now also see the gods and supernatural creatures which are Invisible to Normals. At the advice of his doctor, he begins writing his experiences in the scroll, as he tries, with the help of his friends, enemies, and the gods, to return to his homeland.

Soldier of the Mist was followed by two sequels: Soldier of Arete, which chronicles more adventures in Greece and Thrace; and Soldier of Sidon, where he goes on a journey to Ancient Egypt and the lands down the Nile.

Tropes

 * All Myths Are True: and Latro can see them all.
 * Amazon Brigade: of actual Amazons.
 * Anachronic Order: Latro's amnesia sometimes makes it hard to keep everything in order.
 * Animorphism / Humanity Ensues
 * Author Appeal: Let's see: Unreliable Narrator? Obscure historical references? Playing around with Greek words? Yep, sounds like Gene Wolfe to me.
 * Back From the Dead
 * Badass: Quite a few, but especially Latro
 * Badass Boast: The king of Thrace forces a duel on Latro. When the king tells Latro, "No quarter will be given," Latro notes in his journal that, "I said that I did not think I could kill a man who begged me for his life, but I would try."
 * Big Badass Wolf
 * Bilingual Bonus: The Greek place names are translated to close English equivalents (Athens="Thought"), including an ancient translation error, with the city of "Rope" in "The Silent Country".
 * Black Best Friend: Latro has one, a fellow mercenary from Africa
 * Blessed With Suck: In spite being able to see gods and goddesses, amnesia SUCKS.
 * Deliberate Values Dissonance
 * Everyone Calls Him "Barkeep": "Latro" means "soldier", and is not his real name
 * Everyone Is Jesus in Purgatory: See Wild Mass Guessing
 * Flash Forward: When Latro gets ahead of himself or doesn't write for a long time.
 * Gender Bender
 * God Was My Co-Pilot
 * Golem
 * Greek Mythology
 * Happiness in Slavery
 * Heroic BSOD: And he can't remember why!
 * Istanbul Not Constantinople: See Bilingual Bonus.
 * Jerkass Gods
 * Historical In-Joke: Most of the story.
 * Hollywood History: Averted.
 * Laser-Guided Amnesia: but definitely not Easy Amnesia.
 * Let's You and Him Fight: Latro wrestling a Spartan warrior (with Hercules giving him advice.)
 * Literary Agent Hypothesis
 * Maybe Magic, Maybe Mundane: All of Latro's supernatural experiences could just be hallucinations from his head wound.
 * Meaningful Name
 * Mind Screw: especially whenever Latro gets depressed.
 * Most Definitely Not a Villain
 * Necromancer
 * Note to Self
 * Our Gods Are Greater
 * Our Monsters Are Different: Among other things, centaurs are were-horses.
 * Our Werewolves Are Different
 * People's Republic of Tyranny: Sparta is not a nice place for the Helots.
 * Rage Against the Heavens
 * Really Gets Around: Just because he can't remember their names doesn't stop a lot of women from getting it on with Latro.
 * In fact, at least two used his lack of memory to get into his bed, by claiming they'd already been there.
 * Riddle of the Sphinx
 * Scrapbook Story
 * The Chosen One
 * The Gump: Latro Gumps his way through the ancient world.
 * Theres No Place Like Home:
 * The Spartan Way: As practiced by the actual Spartans.
 * The Undead
 * The Wild Hunt
 * Unreliable Narrator: A Gene Wolfe staple.
 * Unspoken Plan Guarantee: The climax of Soldier of Arete depends on a plan that requires Latro to achieve certain things at certain times over the course of several days. Knowing that he doesn't always read his journal every day, let alone any particular part of it, Latro doesn't describe the plan in his journal, instead only noting that he's confided in one of his friends, who will bring him up to speed every morning. Result: the readers are in the dark until it comes to the description of the plan being carried out.
 * Viewers Are Geniuses: You're pretty much expected to have read or have on hand a copy of Herodotus. The plot makes a lot more sense with it and several elements are completely unclear without it. Also see: Author Appeal.
 * What You See Is What You Get: Latro can see gods. He gets to see a lot of gods.
 * Wild Mass Guessing: existed before this page, somehow.