BEIJING, Jan. 9 -- The protection of historic relics has been a key concern for Chinese President Xi Jinping since he was sworn in.

The following is a chronicle of the president's instructions on the protection of historic relics:

-- In August 2013, Xi urged continuous efforts in protecting the ancient city of Zhengding in north China's Hebei Province,

-- In November 2013, Xi asked local authorities to restore the old Communist Party of China buildings to their original appearance.

-- In February 2014, Xi visited the Capital Museum in Beijing, stressing the retrieval of historical documents and restoration of relics in order to "let the relics speak and teach people the wisdom of the past."

-- In April, Xi ordered authorities to restore the historic sites of "Unit 731," a germ warfare research base established by the Japanese military in Harbin in 1935 and the center of Japan's biological warfare in China and Southeast Asia during World War II.

-- In September, Xi wrote a lengthy instruction to urge repair of a mass grave for victims of Japanese aggression.

-- On October 22, Xi sent a letter for the opening of an exhibition held in France featuring Chinese Han-dynasty (202 B.C.-220) relics.