Leonidas was born in the 540 BC to King Anaxandridas II but his mother is unknown in Sparta. His mother was not only his father’s wife but also his father’s niece. Leonidas had one brother and one half brother. Their names were Porieus and Cleomenes. Leonidas’ brother (Cleomenes) had a child. Her name was Gorgo. Leonidas had an interest in her and they became husband and wife. Cleomenes had his time in the throne after Anazandridas ll died. Eventually, after Cleomenes died, Leonidas took the throne.