Pyrrhonism, or Pyrrhonian skepticism, was a school of skepticism founded by Aenesidemus in the 1st century BC and recorded by Sextus Empiricus in the late 2nd century or early 3rd century AD. It was named after Pyrrho, a philosopher who lived from c. 360 to c. 270 BC, although the relationship between the philosophy of the school and that of the historical figure is unclear. A revival of the use of the term occurred during the 17th century.