The first description of the Postojna Cave dates from the 17th century, when Slovenian scholar Janez Vajkard Valvasor wrote about it in his book The Glory of the Duchy of Carniola.
Esimene Postojna koopa kirjeldus on pärit 17. sajandist, mil seda mainis oma raamatus „Die Ehre des Herzogthums Crain ” sloveenia õpetlane Janez Vajkard Valvasor.