1. Olympias, mother of Alexander the Great
Alexander the Great was one of the most successful military commanders of all time, securing an empire that stretched from the Mediterranean to the Himalayan Mountains. He seems to have inherited much of his moxie from mom.
Alexander's mother, Olympias, was the fourth wife of Alexander's father. Even in ancient times, Olympias got a bad rap: The historian Plutarch accused her of sleeping with snakes as part of her religious rites.
When Alexander's dad took another wife, a Macedonian named Cleopatra, Olympias went into voluntary exile, only to return after her husband was assassinated — an event that some historians suspect Olympias had a hand in. She then had Cleopatra murdered, along with Cleopatra's infant child, helping secure her own son's succession to the throne.
Exactly how ruthless Olympias was is hard to say, said Brian Pavlac, a historian at King's College in Pennsylvania. Historical women often get painted as especially cruel and vicious, Pavlac told LiveScience.
Cruel or not, Olympias' political mechanizations put her at odds with Macedonia's regent Antipater and his son, Cassander, while Alexander was off conquering the globe. Cassander's army eventually captured Olympias, and she was put to death in 316 B.C., outliving her famous son by seven years.