Pleistarchus in Wikipedia
Pleistarchus or Plistarch (Ancient Greek: Πλείσταρχος; d. 458 BC) was the Agiad King of Sparta from 480 to 458 BC. He was the son of Leonidas I and Gorgo. For the early part of his reign, his cousin Pausanias, acted as regent because Pleistarchus was not of age.
A young Pleistarchus has been portrayed by Giovani Cimmino in the 2007 blockbuster 300, inspired by the same graphic novel by Frank Miller and Lynn Varley.
A young Pleistarchus (titled Leo Jr.) is portrayed by Hunter Clary in the 2008 movie Meet the Spartans.