Zoroastrian ritual exposure of the dead is first known of from the writings of the mid-5th century BC Herodotus, who observed the custom amongst Iranian expatriates in Asia Minor. In Herodotus' account (Histories i.140), the rites are said to have been "secret", but were first performed after the body had been dragged around by a bird or dog. The corpse was then embalmed with wax and laid in a trench.