| Pleistarchus | |
| Death Date: | c. 458 BC |
| Succession: | King of Sparta |
| Reign: | 480–459 BC |
| Predecessor: | Leonidas I |
| Successor: | Pleistoanax |
| Father: | Leonidas I[1] |
| Mother: | Gorgo |
Pleistarchus (Greek, Ancient (to 1453);: Πλείσταρχος ; died c. 458 BC) was the Agiad King of Sparta from 480 to 458 BC.[2]
Pleistarchus was born as a prince, likely the only son of King Leonidas I and Queen Gorgo. His grandparents were Kings Anaxandridas II and Cleomenes I.[3] He was born from an avunculate marriage – his parents were uncle and niece.[4] His uncle Cleombrotus was his tutor.[5]
Pleistarchus' father King Leonidas perished in 480 BC at the Battle of Thermopylae. For the early part of Pleistarchus's reign, his uncle Cleombrotus acted as regent; after Cleombrotus's death in 479 BC, Pleistarchus's cousin Pausanias was regent.[6]
It is unknown whether Pleistarchus was married. He died without an heir, and was succeeded by Pleistoanax, son of Pausanias.[7]
He had no known surviving relatives after his death, marking the end of his bloodline.