Agnes of Poitou

Agnes of Poitou (c. 1025 – 14 December 1077) was the queen of Germany from 1043 and empress of the Holy Roman Empire from 1046 until 1056 as the wife of Emperor Henry III. From 1056 to 1061, she ruled the Holy Roman Empire as regent during the minority of their son Henry IV.

After the death of her husband, she proved an inexperienced regent unable to effectively assert her power and secure loyal allies. In Germany, she is still remembered as a sympathetic historical figure, even if a flawed politician.

Source: Wikipedia — https://en.wikipedia.org/wiki/Agnes_of_Poitou