The Song of Achilles by Madeline Miller
Madeline Miller's reimagining of one of the most famous relationships from the Iliad, The Song of Achilles explores the love story between cousins Patroclus and Achilles. It's heartbreaking and beautiful and stays firmly away from the cheesy territory that so much historical fiction stumbles into. Familiarity with the Iliad or even the Wolfgang Petersen movie Troy would be helpful.
Buy it HERE