Fredegund (545 – 597 CE), the queen consort of Chilperic I – the Merovingian Frankish king of Soissons, has a reputation of being one of the most bloodthirsty and sadistic women in history. Accounts by Gregory, the Bishop of Tours (539 – 594 CE), depict her as a murderous lady who achieved power through her husband and used it to keep his kingdom in a state of war for more than forty years. She was also known as an early exponent of dirty warfare who relied heavily on poison and other covert operations

This episode is also available as a blog post: http://martinifisher.com/2022/05/05/fredegund/