Arouet adopted the name Voltaire in 1718, following his incarceration at the Bastille. Its origin is unclear. It is an anagram of "AROVET LI", the Latinized spelling of his surname, Arouet, and the initial letters of ("the young"). According to a family tradition among the descendants of his sister, he was known as ("determined little thing") as a child, and he resurrected a variant of the name in his adult life. The name also reverses the syllables of Airvault, his family's home town in the Poitou region.