This is a relatively well known story involving incest, infidelity, rape, and the use of sex to control the Roman empire at various levels for almost two decades.

It represents power by proxy, or "soft power", and shows just how much control ambitious women had in history over outwardly powerful men. While it's one of the more extreme examples you can find, the evidence suggests that women typically had more power than we give them credit for.

Agrippina was the sister of one Roman emperor, the wife of another, and the mother of a third emperor. This wasn't just luck, either: she carefully schemed all of this and wielded a ton of control over all three men. She also changed the dynamics of Roman politics forever by cementing more and more central control over the empire in the hands of the emperor (because she didn't think they had enough power already).

Her political antics are the subject of entire books, so I am leaving out quite a bit here. But she was involved in the assassination of the second Roman emperor Tiberius, which set up her brother Caligula to inherit the title. With the help of his sister, he strengthened the control that the position of emperor had over Rome. When he was assassinated by concerned Romans loyal to the Senate, she ended up marrying the next empower (Claudius), convinced him to adopt her son Nero, and then continued this policy of central control through his leadership. She later murdered him because he stopped listening to her. Which set up her son, who she had carefully groomed from a young age, to become the next emperor.

The result was one of the most oppressive periods of Roman history: under her son Nero, she enjoyed great privilege and comfort at the expense of the Roman people.

Nero was only 16 when he took the throne, which meant he was young and single, and that created a few problems for Agrippina. She had to vie for control over her son from other women if she wanted to remain in charge. She was extremely suspicious of other women being around him and even had sex with him so he wouldn't be "tempted" by other women.

This would eventually be her downfall though. Nero ended up killing her, likely at the behest of one of his lovers, because they felt threatened by his mother's control over him.

The story of Agrippina is one where she kept pushing the men in her life, including her own son, to become more and more ambitious so that she could enjoy the fruits of their power. By some accounts, Nero never wanted to be emperor, and his failures as one of the most hated Roman emperors of all time can be traced back to this.

Sources:

https://medium.com/lessons-from-history/sex-life-of-agrippina-onset-of-neros-reign-5f60749b4d61

https://www.historytoday.com/archive/months-past/death-emperor-claudius

Some formal research about power wielded by women, often against or through "patriarchs" in history, can be found here:

Van Creveld, M. (2013). The privileged sex. DLVC Enterprises.
http://www.faculty.fairfield.edu/dcrawford/rogers.pdf
https://www.britannica.com/topic/role-of-Nigerian-women-1360615
https://www.oxfordhandbooks.com/view/10.1093/oxfordhb/9780199582174.001.0001/oxfordhb-9780199582174-e-036
https://ora.ox.ac.uk/objects/uuid:2e88e3f6-b270-4228-b930-9237c00e739f/download_file?file_format=application/pdf&safe_filename=Item.pdf&type_of_work=Journal%20article
https://anthrosource.onlinelibrary.wiley.com/doi/pdf/10.1525/ae.1975.2.4.02a00090
Woman as a Force in History. Mary Beard, 1946. https://www.marxists.org/archive/beard/woman-force/index.htm
https://theanarchistlibrary.org/library/dominique-karamazov-the-poverty-of-feminism
Kelly Mullane, M. (1970). Women and their Role in Shaping Society. Occupational health nursing, 18(6), 7-9. https://journals.sagepub.com/doi/pdf/10.1177/216507997001800601
They Were Her Property: White Women as Slave Owners in the American South. https://www.jstor.org/stable/j.ctvbnm3fz
Dannenbaum, J. (1981). The origins of temperance activism and militancy among American women. Journal of Social History, 235-252.
Melissa Strong, (2018) Women and the Temperance Movement. Retrieved from the Digital Public Library of America. http://dp.la/primary-source-sets/women-and-the-temperance-movement