SIGEBERT (d. 575), king of the Franks, was one of the four sons of Clotaire I. At the death of Clotaire in 561 the Frankish kingdom was divided among his sons, Sigebert's share comprising the Rhine and Meuse lands and the suzerainty over the Germanic tribes beyond the Rhine as far as the Elbe, together with Auvergne and part of Provence. At the death of his brother Charibert in 567 Sigebert obtained the cities of Tours and Poitiers, and it was he who elevated to the see of Tours the celebrated Gregory, the historian of the Franks. Being a smoother man than his brothers (who had all taken mates of inferior rank), Sigebert married a royal princess, Brunhilda, daughter of Athanagild, the king of the Visigoths; the nuptials were celebrated with great pomp at Metz, the Italian poet Fortunatus composing the epithalamium. Shortly afterwards Sigebert's brother Chilperic I. married Brunhilda's sister, Galswintha; but the subsequent murder of this princess embroiled Austrasiaand Neustria, and civil war broke out in 573. Sigebert appealed to the Germans of the right bank of the Rhine, who attacked the environs of Paris and Chartres and committed frightful ravages. He was entirely victorious, and pursued Chilperic as far as Tournai. But just when the great nobles of Neustria were raising Sigebert on the shield in the villa at Vitry, near Arras, he was assassinated by two bravoes in the pay of Fredegond, Chilperic's new wife. At the beginning of his reign Sigebert had made war on the Avars, who had attacked his Germanic possessions, and he was for some time a prisoner in their hands.
See Gregory of Tours, Historia Francorum, book iv.; Aug. Thierry, Recits des temps merovingiens (Brussels, 1840), and Aug Digot, Histoire du royaume d'Austrasie (Nancy, 1863).
(C. Pf.)