An invaluable Byzantine manuscript that was stolen from the monastic community of Mount Athos half a century ago was returned by American authorities to Greece via the Greek Embassy in Washington.

The manuscript, known as “menologion,” was bought by Duke University that subsequently discovered that it had been stolen from Dionyssiou monastery on Mt. Athos almost 50 years ago. Dated to around 1050, it consists of more than 500 parchment pages full of Greek Orthodox saints’ biographies for a particular month.

Greek Ambassador to the U.S. Christos Panagopoulos on Friday thanked on behalf of the Greek state the Duke University and the American authorities “for their professionalism and undivided support to Greece’s request” for the manuscript’s return.