She was married to Agamemnon , King of Mycenae . With the help of troops from his new father-in-law , Agamemnon then took the throne of Mycenae from his uncle Thyestes . Agamemnon and Clytemnestra became rulers of Mycenae , and she bore three daughters : Iphigenia , Chrysothemis , and Electra ; and finally a son : Orestes .