The historical tablets belong to Darius I, also known as , who ruled the Achaemenid Empire in the 5th century BC.

The return of the tablets takes place following the intensive negotiations of Iran’s ministries of foreign affairs and cultural heritage and the legal department of the presidential office with the Institute of Oriental Studies at the University of Chicago.

These tablets are often written in cuneiform and in Elamite or Aramaic language in different shapes and sizes, and their subjects are mainly related to the management of resources, roads, social relations, basic necessities of life, wages and the economy of the Achaemenid society during Darius I.

Cuneiform is a writing system that was used to write several languages of the Ancient Near East.