After the death of Tyndareus, Meneleaus became king of Sparta. He used the Spartan army to drive out Aegisthus and Thyestes from Mycenae and place Agamemnon on the throne. Agamemnon extended his dominion by conquest and became the most powerful ruler in Greece.
Following Tyndareus' death, Menelaus took over as king of Sparta. He used the Spartan army to remove Aegisthus and Thyestes from Mycenae and install Agamemnon as their new leader. Agamemnon then expanded his rule through conquest, becoming the most powerful ruler in Greece.