The phrase “Pandora’s box” entered European literary culture through the Renaissance scholar and writer Erasmus. In his Latin work Adagia, Erasmus helped popularize the image of Pandora’s container as a box rather than the large jar described by Hesiod.
The change reflects a translation and interpretation history rather than the wording of the earliest Greek account. Hesiod uses pithos, a large storage jar. Later Latin and European traditions associated the container with a smaller box, and that version became dominant in English and other modern languages.
Erasmus was a major sixteenth-century humanist whose collections of proverbs and classical references circulated widely among educated European readers. His work helped transmit and reshape ancient material for Renaissance audiences.
The modern idiom now means a source of unexpected complications or troubles released by an apparently simple action. Although the phrase is famous, the “box” is technically a later development, not the object named in Hesiod’s original story.