The castle chapel of Saint-Saturnin-lès-Apt dominates the primitive village of the 10th and 11th centuries. Improperly called a castle, it actually constitutes a Romanesque chapel adjoining a massive keep located behind the church. Arrow slits, whose location is still visible, were plugged during the extension of the chapel and its annexation to the military part of the complex between 1672 and 1688.