Atreus was the oldest son of Pelops and Hippodamia; he is remembered as mad murderer with a reign as king unrivaled for the amount of blood spilled and lives taken. The myth of Atrues starts (in most versions) with the terrible murder of his stepbrother, Chrysippus, an act that would lead him down a bloody path, and eventually to his death. Atreus killed Chrysippus along side his brothers Thyestes (mentioned on the site) and Alcathous (not mentioned) out of fear of his succession to the throne. For this bloody act the three brothers were driven from their kingdom of Pisa, after which Alcathous went his seperate ways from Atreus and Thyestes. Atreus and Thyestes stayed together and found their way to the kingdom of Mycenae, the place soon to be the site of their future atrocities and battles for kingship. At the time of the brothers arrival the king of Mycenae, Eurystheus, was away fighting the heracleidae leaving the people in search of a king. The Delphic oracle advised the people to pick between one of the pelopids, Atreus or thystes. Thystes manipulates Atreus into making him king, which Atreus discovers soon after and goes to seek advice from Zeus. Atreus, post divine intervention, is made the rightful king of Mycenae, and thus begins a complicated chain of crimes over the throne. Atreus kills his own son, Pleisthenes, because of Thyestes; kills and butchers his nephew(s) then presents them to Thyestes (their father) for dinner; is chated on by his wife with his brother; rasies his brother's child, Aegisthus, thinking it's his, and is ultimately killed by his brothers son, Aegisthus, who he raised.
Thyestes was the second oldest child of Pelops and Hippodamia; he is remembered as a jealous man who took no mercy when it came to geetting what he wanted. His starts, same as his brother, with the murder of his step-brother, Chrysippus, along side Atreus and Alacathous. Thyestes ended up in Mycenae with his brother, which is the start of the long, dark and tragic battle for kingship between the two. The first atrocity Thyestes committed was an affair with his brothers wife, Aerope. Thyestes used his relationship with Aerope to get her to manipulate Atreus into picking a way to decide kingship which would give him the throne. Atreus however turned to the gods and, with their help, still become king. Thyestes life after this is filled atrocites all in a vain attempt to be king. Thyetes gets his nephew killed; is tricked into eating his own son(s); rapes his own daughter due to a prophecy saying the child they bore together will kill Atrues; kills his brother; and dies untimely to his nephews' hands.