Queen of the Silver Arrow by Caroline Lawrence
Few have ever seen her, but all of Laurentum knows the story of Camilla - tied to a spear and thrown across a river by her father as he fled for his life. The Goddess Diana saved the baby, and now it is Camilla's turn to save Laurentum as the Trojans march on the town. But Camilla is a wild girl from the forest, not the Amazon they imagine, and so Acca must step in to help her new friend adjust to the great destiny before her. Particularly suitable for struggling, reluctant and dyslexic readers aged 12+