Leonias (Greek: Λεωνίδας; "Lion's son", "Lion-like") was a king of Sparta, the 17th of the Agiad line, one of the sons of King Anaxandridas II of Sparta, who was believed to be a descendant of Heracles, possessing much of the strength and bravery that made his ancestor famous. While it has been established that King Leonidas of Sparta died at the Battle of Thermopylae in August, 480 B.C., very little is known about the year of his birth, or for that matter, his formative years. Paul Cartledge, the distinguished scholar and historian who has written countless volumes relative to the Spartans, has narrowed the date of the birth of King Leonidas to around 540 B.C. Therefore, if it is assumed that Leonidas was born anywhere in the years subsequent to 540 B.C., this would have placed him in the 50+ year old range. Leonidas was one of three: he had an older brother Dorieus and a younger brother Cleombrotus, who ruled as regent for a while on Leonidas' death before the regency was taken over by Pausanias, who was Cleombrotus' son. Leonidas succeeded his half-brother Cleomenes I, probably in 489 or 488 BC, and was married to Cleomenes' daughter, Gorgo. His name was raised to heroic status as a result of the events in the Battle of Thermopylae.