They are important witnesses of the history of the text of New Testament and Septuagint.
Four manuscripts were bought on 19 December 1906 from an Arab dealer named Ali in Giza, not far from Cairo.
Upon the next expedition to Egypt, Freer met with Ali and acquired a Coptic codex of the Psalms and the earliest papyrus codex of the Minor Prophets.
Formerly these manuscripts were held in Detroit, Michigan, in Freer's private collection.
He gave his art collections to the United States together with funds for a building to house them.