South Korea on Monday revealed to media for the first time some of the ancient royal Korean books retrieved from France earlier this year. France returned the books through a renewable lease in four shipments from April to May after keeping them at the French national library for decades. The 297-volume \"Oegyuganggak,\" which details the protocols of royal ceremonies and rites of the Joseon Dynasty (1392-1910), were looted by French troops in 1866 when they invaded Ganghwa Island in retaliation for Koreans\' persecution of French Catholic missionaries. The books are currently in storage at the National Museum of Korea in central Seoul. The five books shown to media on Monday described the essence of each royal ceremony and rite and included the oldest one titled \"Pungjeongdogam Uigwae\" (1630), according to the museum. \"Three of the five books are the only remaining copy and had not been kept in Korea,\" a museum official said. In addition to the royal books, parts of their original silk covers were displayed. The museum said it is important to know how the books\' covers, which the king used, changed from the 17th to 19th centuries. France also returned the original book covers to South Korea along with the royal texts. At France\'s national library, most of the covers were removed from the books in the 1970s and stored separately, museum officials said. The museum plans to hold a special exhibition of the retrieved royal books from July 19 to Sept. 18. The return came after South Korean President Lee Myung-bak and his French counterpart, Nicolas Sarkozy, agreed in November to transfer the books on a renewable lease. Seoul had long sought to retrieve the Oegyujanggak books. Former French president Francois Mitterrand returned one of the books on a permanent lease basis in 1993, but the other volumes had remained in France.