Achilles and Patroclus.

There are two kinds of novels about Antiquity; The 'historical' novels like "Quo Vadis" and "I, Claudius." and there are novels about a character from mythology. I prefer the Latter Because there is more room for fantasy and imagination. In the 1970's the German writer Christa Wolf wrote some outstanding novels about mythology like "Medea" and "Cassandra". (The Latter translated into English.)
And now there is Madeline Miller.

Although the title of the novel is "The Song of Achilles" It could be "The Song of Patroclus". Patroclus is the narrator and though Achilles is the main character, he tells us about his own feelings and thoughts. It contrasts with Homer's Iliad where Patroclus is a rather anonymous and faceless character.

When Patroclus is exiled to Phtia, he lives there with children of nobility and among them Achilles son of Peleus, king of Phtia. Patroclus and Achilles become best friends and after awhile even more than just friends.
One day a message arrives: Paris, a Troy-en prince, has abducted Helen, wife of Menelaus. All the Greek kingdoms will join together and sail to Troy and bring back Helen.

A slow paced, step by step description of the growing friendship and yet you are compelled to read page after page as if you are reading a thriller. You have to be a gifted writer to pull off did. She Describes human feelings and thoughts with a lot of sensitivity and caring. A good Example is the young woman named Briseis, a captive (The Greeks were landed on Troyen soil). Miller Describes her feelings and fears in a way did you feel sad for Briseis Because of the things she has to endure. The factthat she loves Patroclus makes her even more likable.

The last chapters of the novel are very beautiful and theyhave a personal interpretation did goes beyond the mythological tradition.
Recommended.