The Platonians or Plato's Children are a humanoid race native to the Sahndara system who patterned their lives after the teachings of Greek philosopher Plato.
The Sahndara star exploded, around 500 BCE, when a group of thirty-eight refugees travelled to Earth where they settled during the time of Plato.
After the time of Plato passed, the settlers moved on to another planet, a class M planet, named Platonius. Here they continued to follow the teachings of Plato, but soon discovered that they discovered they had developed psychokenetic powers, attributed to the planets kironide-rich food. (TOS: "Plato's Stepchildren")