Four stained glass windows inside the church of Notre-Dame de la Victoire du Sabart tell the story of a battle between Charlemagne and the Moors at Tarascon-sur-Ariège in 778 CE. But to put the battle in context, we need to begin a little earlier with Charlemagne’s siege of Zaragoza and the slaughter of his rearguard at the pass of Roncesvalles.