Twenty-two historic artifacts, including six portraits of monarchs of the Ryukyu Kingdom believed to have been taken outside Japan during the 1945 Battle of Okinawa, were discovered in the United States and returned to Okinawa, the Okinawa Prefectural Government announced last month.

It is the first time that a portrait of a Ryukyu king, known as Ogoe, has been confirmed to still be in existence.

It is also the first time in 70 years that materials related to the Ryukyu Kingdom, which had been taken to the U.S. in the aftermath of World War II, have been brought back, according to the Okinawa government.