The Lettres provinciales (Provincial letters) are a series of eighteen letters written by French philosopher and theologian Blaise Pascal under the pseudonym Louis de Montalte. Written in the midst of the formulary controversy between the Jansenists and the Jesuits, they are a defense of the Jansenist Antoine Arnauld from Port-Royal-des-Champs, a friend of Pascal who in 1656 was condemned by the Faculté de Théologie at the Sorbonne in Paris for views that were claimed to be heretical. The first letter is dated January 23, 1656 and the eighteenth March 24, 1657. A fragmentary nineteenth letter is frequently included with the other eighteen.