Alexander was born in 356 BC to King Philip and his wife Olympias, a native of a border area with Albania known as Epirus. Historians describe Olympias as an emotional woman who believed in unusual cults, worshiped Dionysus (god of ecstasy and possession), and handled snakes. It is believed that Philip became infatuated with Olympias when she was 14 at the celebration of the mystery cult on the island of Samothrace. However, it was also a political savvy move in that his marriage sealed an alliance with western principalities. Legend holds he grew disenchanted years later when he saw her with a snake in her bed.
Eventually, Philip shunned Olympias for a younger wife who bore him another heir. (Polygamy was practiced among Macedonian royalty). Afterwards, Alexander lived in Epirus for a time with his mother, only to return to insults over Philip's new wife and heir. A close and potent pair, Alexander allowed his mother to have this wife and her child put to death when he assumed the throne. (Wood, pg. 24)
As a child, Alexander would exhibit characteristics gleaned from both his parents. Like Philip, fearlessness and an ability to evaluate a situation were apparent in the story of Bucephalas (ox head), an untamable horse which Alexander wagered his father he could master. Noticing the horse jumped at its own shadow, the young Alexander led Bucephalus straight into the sun, mounted the horse and rode away. His skill at military strategy was admired at Chareonea, and he is said to have questioned Persian envoys about the geography of their land. Like Olympias, Alexander was temperamental, believed in oracles and omens and developed an interest in cults.