In 561 Sigibert succeeded his father to the kingdom of Austrasia. He battled invasions by the Avars, a fierce nomadic tribe related to the Huns. He therefore moved his capital from Rheims to Metz between 567 and 568. He added to his lands those of his deceased brother Charibert I and approved the election of Gregory as Bishop of Tours.Sigebert was assassinated in a family blood fued by his brother Chilperic. Chilperic had his own wife, Galswintha, murdered so he could marry her maid. Sigibert was married to Brunhild, sister of Galswintha. Freudegunda, Chilperic's new wife was vicious and evil and among others had Sigiberth murdered. On Sigibert's death, his wife, Brunhild, continued seeking revenge for her sister's and her husband's murders.