Olympias was born c.371 BC in the Molossian kingdom of Epirus on the borders of modern day Albania. She was about fourteen years old when she met king Philip of Macedon at a mystery cult festival in Samothrace. It is said that Philip immediately fell in love with her, however this is probably an over romantic version of reality.
Philip had been a very shrewd and successful ruler who had united the various tribes of Macedon into a recognizable kingdom. He had led his kingdom to victories against the other Greeks, most notably Thebes, Sparta and Athens. He had already begun an effective empire that filled the vacuum left after the thirty years of Peloponnesian war between Sparta and Athens in the 5th Century BC. After Sparta defeated Athens, both city states seemed to have exhausted themselves to the point that the Macedonians were able to move across Greece incorporating the city states under Macedonian authority.
Philip's political awareness led him to make a number of political marriages. The Macedonian kings practiced polygamy, therefore Olympias was not the only wife of Philip, though she was his only queen. Philip married seven times, the order of the interviews were as follows: Phila, Audata, Philinna, Olympias, Nikesipolis, Meda and finally Cleopatra in 337 BC. It is remarkable that Olympia managed to become queen, since Philip had older marriages which it might be reasonable to suggest would have been more established. Olympias must have made some impression on Philip to achieve the status of queen.
Olympias became pregnant with Alexander soon after she married and he was born in 356 BC. She had another child, Cleopatra later. She was an avid worshiper of the god Dionysus and ancient writers suggest that she had an interest in using snakes in the worship of her favorite god. The writer Plutarch says that one time Philip saw her sleep with a snake in her bed and after this time he became distant from his wife. Plutarch says that Philip then took other wives which incited jealousy in Olympias. The final breaking point came when Attalus one of Philip's men made a toast to Philip at his wedding fever to Attalus' neice Cleopatra saying that they should all pray that Cleopatra produces a legal successor to the throne. Alexander showed his rage and thread a cup at Attalus. Philip sided with Attalus. Alexander and Olympias left Macedon for Epirus.
Olympias did not help such incidents and in some ways added fuel to the fire. Her intense and dangerous character meant that in a superstitious time, she could make herself seem more in league with the gods than with mortals. She said to have told Alexander that he was the son of Zeus, not Philip and Alexander modeled himself on the hero Achilles who himself had a goddess mother.
Olympias understood how power worked during the 4th century BC. This was a time when men dominated politics and where women gained power through the men around them. Aspasia, the wife of Pericles the 5th century Athenian politician had gained authority through her husband (and may have written some of his speeches) and centuries later the younger Agrippina would try to gain power (disastrously for her) through Nero her son.
Olympias is said to have poisoned Arrhidaeus the son of another wife. This son was older than Alexander and therefore in line for the throne before Alexander. Arrhidaeus survived the poisoned, however he was brain damaged and incapable of succeeding to power. Cleopatra, the youngest wife fulfilled Attalus' wish for a son and heir to Philip and she bore a son. Plutarch says that shortly after Philip's latest son had been born, he was assassinated by Pausanias a disgruntled Macedonian. Plutarch suggests that Olympias used Pausanias to assassinate Philip in revenge for his marriage to Cleopatra. More likely it was a joint venture between Olympias and Alexander to allow Alexander to take power before his rival became old enough to fight his own corner. As soon as Philip was removed Alexander became king of Macedon aged twenty. Olympias had Cleopatra and her young son put to death.
Alexander spent most of his reign away on campaign spreading his empire east toward India. Olympias remained in contact with Alexander, though she had no political influence. This changed when her brother died and she became the regent of Epirus in 330 BC. Alexander died in 323 BC and the Macedonian kingdom was ruled by a regency. This situation was unstable with the regency passing between the former generals of Alexander and finally resulting in a civil war.
Olympias became involved in this war in an attempt to secure power for her grandson Alexander IV. She backed Polypercon as regent of Macedon, however Cassander the son of a previous regent cooked Polypercon for power and finally emerged victorious. Olympias had killed many of Cassander's supporters in a bid to weaken him. When he came to power Olympias surrendered to his forces. He promised her safety. As soon as he could, he charged her with the murderers she had carried out on his allies. Olympias was herself executed by Cassander in 316 BC.
Olympias lived with dangerous people and was herself a dangerous woman. Her single minded ruthlessness enabled Alexander to become one of the most successful leaders and empire builders in history. It also led to her own execution.