< Atreus, son of Pelops >
1 Origin
Atreus was born in Pisa, Eleia, in 1290 BC.
Atreus' father was Pelops, son of Tantalus. [Apo.E.2.10, Hyginus.124, Paus.9.40.11]
1.1 Atreus' mother
Atreus' mother was not Hippodamia, but was presumably Perseus' daughter, based on the following:
1) Pelops is known to have had more than 15 sons, but Hippodamia is said to have had six. [Pind.Ol.1.89]
When creating a genealogy, Atreus was born more than 20 years after the marriage of Pelops and Hippodamia. Also, Atreus, or Thyestes, was the firstborn. [Euri.Scho.Or.5.1, 12.3, Tzetzes.1.420]
This means that Atreus' mother was not Hippodamia, and Atreus was likely born to another woman.
2) Sthenelus left Mideia to Atreus and Thyestes. [Apo.2.4.6]
If their mother was Hippodamia, they were the brothers of Sthenelus' wife.
If their mother was the daughter of Perseus, they were the nephews of Sthenelus.
It is more reasonable to think that Sthenelus did not leave Mideia to Atreus and Thyestes over their older brothers, but left the city to his blood nephew.
3) After the death of Eurystheus, Atreus inherited Mycenae. [Diod.4.58.2]
Thucydides reports that Eurystheus, the son of Sthenelus, left Mycenae in the hands of Atreus, who happened to be there when he set out to fight the sons of Heracles. [Thucy.1.9]
However, Thucydides' theory is not convincing.
Atreus was the brother of Nicippe (or Archippe), the wife of Eurystheus' father Sthenelus.
In other words, Atreus inherited Mycenae as Eurystheus' uncle-in-law.
However, if Atreus' mother was the daughter of Perseus, Atreus would have inherited Mycenae as Eurystheus's blood cousin, which would make sense.
4) Atreus' two grandsons married the daughters of Tyndareus. [Pauss.2.22.3, 6]
There seems to be no blood relationship between Atreus, son of Pelops of Mycenae, and Tyndareus, son of Oebalus of Sparta.
However, if Atreus' mother was a daughter of Perseus, Atreus would be the son of the sister of Tyndareus' mother, Gorgophone. In other words, Agamemnon and Menelaus married the daughters of their father's cousin, Tyndareus.
Perseus is said to have two daughters, Gorgophone and Autochthe. [TzeAdLyco.494]
It is assumed that Atreus' mother was Autochthe. [Apo.2.4.5, Pauss.3.1.4]
2 Family
Atreus had a son, Pleisthenes (or Plisthenes). [Euri.Scho.Or.5.1]
Atreus had a daughter, Kydragora. [FGrH.Nr333.F180]
3 Others
3.1 Migration to Macistus
In 1287 BC, Atreus emigrated from Pisa to Macistus in Triphylia with his brother Thyestes. [Euri.Scho.Or.5.1]
Atreus' half-brothers also left the town at the same time, and it is assumed that an important event occurred in Pisa. As legend has it, it may have been related to the death of Chrysippus, the successor of Pelops. [Paus.6.20.7]
3.2 Migration to Midea
In 1277 BC, Atreus emigrated to Midea in Argolis with his brother Thyestes. [Apo.2.4.6]
After Electryon of Midea died and his son Licymnius and daughter Alcmena left for Thebes, Sthenelus, son of Perseus, left Midea to Atreus and Thyestes. [Apo.2.4.6]
Atreus was the brother of Sthenelus' wife Nicippe (or Archippe), but he had at least six older siblings. [Pind.Ol.1.89]
It is presumed that Sthenelus left Midea to Atreus and Thyestes because they were the sons of Sthenelus' sister, not because they were the brothers of Sthenelus' wife.
3.3 Founding of Cleonae
In 1251 BC, Atreus migrated north from Midea and founded Cleonae. [FGrH.Nr2.F3, FGrH.Nr333.F20]
The reason for Atreus' migration is believed to be the return of Licymnius, the son of Electryon, who lived in Thebes. Midea was ruled by Electryon, but after Electryon's death, Licymnius lived under Amphitryon in Thebes. [Apo.2.4.8]
3.4 Heracles' attack
In 1243 BC, Heracles attacked Cteatus and Eurytus, the sons of Actor, who lived in Hyrmina in Eleia, at Cleonae. [Apo.2.7.2, Diod.4.33.4, Paus.5.2.1]
Many Cleonaans participated in this raid. [Aelia.4.5]
Atreus led the Cleonaans and is thought to have cooperated with Heracles.
Heracles was the son of Alcmena, daughter of Atreus' sister Eurydice (or Lysidice).
3.5 Succession of Mycenae
In 1217 BC, Atreus succeeded Eurystheus and moved from Cleonae to Mycenae. [Diod.4.58.2]
This was because Eurystheus, the son of Sthenelus, who ruled Mycenae, was killed in battle with the sons of Heracles.
Atreus was the son of the sister of Sthenelus, father of Eurystheus, and Atreus inherited Mycenae as Eurystheus' cousin.
This succession of Mycenae by Atreus left a legacy of trouble with the Heracleidae.
The sons of Heracles were direct male descendants of Perseus, the founder of Mycenae, and the Heracleidae had a higher order of succession to Mycenae than the descendants of Atreus.
3.6 Death of Atreus
There is a legend that Atreus was killed by Aegisthus. [Hyginus.88, Tzetzes.1.450]
However, since Aegisthus was not killed by Agamemnon, it is believed that Atreus died of illness or natural causes.
Atreus is estimated to have been 87 years old when he died.