The narratives which are depicted in the lower section of the windows show the defeat of King Chilperic by his brother Sigebert, the protection of Chilperic by the Bishop of Tournai, and the plotting and assassination of Sigebert by Chilperic's wife Queen Fredegund.
A contributor to the Chronicle of Fredegar states (iv. 87) that the army of Sigebert was betrayed from within its own ranks by men of Mayence, in a battle fought with Radulf on the banks of the Unstrut in Thuringia.
When Sigebert I of Austrasia died in 575, Chilperic sent Desiderius to invade his kingdom, but Guntram of Burgundy sent the patrician Mummolus against him and Desiderius was defeated and forced to retreat, leaving Austrasia to Sigebert's son Childebert II.
When Sigebert was assassinated later that year (575), Chilperic invaded the kingdom, but Guntram sent his general Mummolus (always Guntrams main weapon, for he was the greatest general in Gaul at the time) to remove him and Mummolus defeated Chilperic's general Desiderius and the Neustrian's forces retreated from Austrasia.
But at Sigebert's moment of triumph, when he had just been declared king by Chilperic's subjects at Vitry-en-Artois, he was struck down by two assassins working for Fredegund.
According to the pseudohistorical Dossiers Secrets d'Henri Lobineau and related documents, Sigebert IV, on the assassination of his father Dagobert II, was rescued by his sister and smuggled to the domain of his mother the (otherwise unknown) Visigoth princess, Giselle de Razès in Rennes-le-Château.