In Veronica Roth’s young-adult novel Divergent, the protagonist known as Tris was born Beatrice Prior.
Beatrice grows up in the Abnegation faction, one of the society’s five factions. At the Choosing Ceremony, she selects Dauntless and adopts the name Tris. The change marks both her new social identity and her growing independence from the expectations of her family.
The novel was published in 2011 and begins the Divergent trilogy. Tris’s aptitude testing reveals that she does not fit neatly into a single faction, making her “divergent” in the series’ terminology. Her identity becomes increasingly important as the faction system begins to break down.
The surname can cause confusion because “Prior” is her family name, while “Tris” is her chosen shortened name. Beatrice Prior is the character’s birth name, not a separate person in the story.