Leonidas was born around 520 B.C. to King Anaxandridas II, a son of Hercules. Anaxandridas had two wives therefore Leonidas had an older half-brother, Cleomenes, along with his other brother Dorieus and younger brother Cleombrotus I. Cleomenes was thought to succeed Anaxandridas’ throne after his death because he was the firstborn but, he was son of his second wife so his claim to the throne was not entirely genuine. The throne should’ve gone to Dorieus as Anaxandridas’ eldest son by his first marriage but, was held off until further thought.
It is not certain why Cleomenes supported Dorieus in several foreign expeditions. It is thought that he feared him dearly as a rival or because Cleomenes really had an interest in the trips. Fortunately for Cleomenes, Dorieus was killed on one of these expeditions. In no surprise, Cleomenes faced many rivals. One of his greatest political rivals was the co-king Demartus. The two Spartan kings tampered with each others plans for several years until both kings were finally exiled. Demartus snaked his way into Persia where he became the advisor to Xerxes, who would later be king. It was Demartus who warned Xerxes not to underestimate the Spartans anytime at battle.
Cleomenes was later accused of being insane and was put in prison under the orders of his brothers, Leonidas and Cleombrotus. Eventually he was found with pieces of his flesh cut off of his body with a bloody knife that lay on the floor next to him. It is still a mystery whether he committed suicide or he was murdered.
Cleomenes had one daughter, Gorgo, who was married to Leonidas. As a result, Leonidas then became king. He inherited a city-state in danger of being overrun by the Persians. Leonidas would not stand for it and swore he would have it taken care of. When Darius (of Persia) died in 486 B.C., he throne was succeeded by his son Xerxes, who set out to conquer Greece. Xerxes sent messengers to numerous city-states and demanded a tribute of...