After the death of King Eurystheus (of Heracles 12 Tasks fame), Pelops’ son Atreus was installed in Mycenae as King. It’s a bit complicated how this happened though…
Pelops had won Olympia as well as Hippodamia. Their sons, Atreus and Thyestes, murdered their half-brother Chrysippus in order to get the throne of Olympia (?) For the shame of their blood-act, they, and their mother who had supposedly egged them on, were exiled and sought refuge in Mycenae – where Hippodamia killed herself. Atreus took the throne in the absence of Eurystheus, fighting battles abroad, who then died, leaving him to it. But, Atreus was then tricked by Thyestes, who usurped him with the help of Aerope – Atreus’ wife. The gods Hermes and Zeus helped Atreus get the throne back. In revenge for Thyestes sleeping with his wife, Atreus took a cold revenge: he killed Thyestes’ sons and served them secretly to him as a meal. Realising he had eaten human flesh, Thyestes went into exile.
Thyestes asked an Oracle for advice, and was told to sleep with his own daughter, Pelopia, to have a son who would avenge him. This he did, but Pelopia abandoned the child of incest out of shame. This child, Aegisthus, was discovered by a shepherd, who gave him to Atreus to raise as his own son. When he came to adulthood, his real father Thyestes revealed the true nature of their relationships… and Aegisthus fulfilled the prophecy of killing Atreus.
Atreus and Aerope had had several children: Agamemnon – who became king of Mycenae – Menelaus – who went off to Sparta, got chosen by Helen (*that* Helen) as husband and also took the throne – and Anaxibia – who was a girl and thus just got married off at some point. Helen then absconded/was kidnapped by Trojan Paris, the whole Trojan War got underway, and Agamemnon made a rather iffy leadership decision in sacrificing his daughter Iphigenia to get a prevailing wind. This angered Clytaemnestra – Agamemnon’s wife (and sister of Helen) no end, and while he was away she took up with Aegisthus.
So to our comic: when Agamemnon got home from Troy, with the cursed Trojan seer Cassandra in tow, he didn’t last the night, famously being murdered in his bathtub by Clytaemnestra and Aegisthus. (Who later get revenged-on by Clytaemnestra’s own children…)
Thus, the extremely messy story of the Atreides.