Fredegunde (frē´dəgŭn´də), c.545–597, Frankish queen. The mistress of King Chilperic I of Neustria, she became his wife after inducing him to murder his wife Galswintha (567). Fredegunde and Brunhilda, Galswintha's sister and wife of King Sigebert I of Austrasia, were among the leading figures in the long war (561–613) between the Frankish kingdoms of Neustria and Austrasia. Fredegunde procured the deaths of Sigebert I and of her own stepchildren. After Chilperic's murder (584) she acted as regent for her son Clotaire II.