The Cyrenaics or Kyrenaics (Ancient Greek: Κυρηναϊκοί; Kyrēnaïkoí) were a sensual hedonist Greek school of philosophy founded in the 4th century BCE, supposedly by Aristippus of Cyrene, although many of the principles of the school are believed to have been formalized by his grandson of the same name, Aristippus the Younger. The school was so called after Cyrene, the birthplace of Aristippus. It was one of the earliest Socratic schools.