In Greek mythology, Pandora opened a jar, despite later retellings calling it a box. Hesiod’s Greek word is pithos, a large storage vessel commonly used for grain, oil, or wine. The familiar phrase “Pandora’s box” developed because later translators and artists replaced the jar with a smaller box-like container.
The story appears in Hesiod’s Works and Days, composed in the Archaic period. Zeus had Pandora created and sent to humanity after Prometheus gave humans fire. The jar contained evils or troubles that escaped when Pandora opened it. Hope remained inside after she closed the vessel.
The image of a box became especially influential through Renaissance and later European art. This is why modern readers often remember a box even though the earliest surviving literary account specifies a jar. The container’s exact shape and material are not described in detail by Hesiod, so “jar” is the safest canonical answer rather than a more specific pottery type.