Ancient royal books that France returned to South Korea after 145 years were revealed to the media for the first time on Monday.

The National Museum of Korea on Monday disclosed to the media five books out of the total 297 “Oegyujanggak” volumes. The royal books were returned to South Korea between April 14 and May 27 in four batches.

The books, which French troops looted from Ganghwa Island in 1866, were part of a royal library during the Joseon Dynasty. They were stored at the National Library of France since the French invasion.

The volumes describe the protocols of royal ceremonies and rituals in the form of writings and drawings.