Prince Mikasa, uncle of Emperor Akihito, turned 100 years old on Wednesday.

The prince is the oldest member of the Imperial family, living through the reign of three different Emperors in the Taisho, Showa and Heisei eras. He is the only living royal family member to have served in the military during the Sino-Japanese war from 1937 and the Pacific Theater of World War II.

“Nothing will change just because I turn 100 years old,” the prince said in a statement issued through the Imperial Household Agency.

“I’d like to spend my days pleasantly and peacefully while praying for the happiness of people around the world and thanking my wife, Yuriko, who has been supporting me for more than 70 years,” the prince said.

The prince has been in good health condition after recovering from heart surgery in 2012, an agency official said.

Together with Princess Yuriko, 92, Prince Mikasa routinely exercises for about 30 minutes a day at their residence in Motoakasaka, Tokyo, according to the agency.

The prince often reads newspapers and enjoys watching sumo and music programs on TV, and is often taken for a walk in his wheelchair near his residence.

He rarely goes out for official duties or other purposes due to his age. But last May, he watched a rehearsal of an ancient equestrian art show at the Imperial Palace and waived his hands cheerfully to agency officials at the place.

Prince Mikasa was born on Dec. 2, 1915, the fourth son of Emperor Taisho. His eldest brother was Emperor Hirohito, posthumously called Emperor Showa.

The prince served as an officer in the Imperial Japanese Army after graduating from the army’s college. He was posted to Nanjing, China, under a pseudonym for one year from 1943. In a book published after the end of the war, he expressed a sense of guilt over his failure to fully grasp the criminality of war.

With his wife Princess Yuriko, Prince Mikasa had three sons and two daughters. Prince Takamado, Tomohito and Katsura all predeceased him, in 2002, 2012, and 2014, respectively.

He has nine grandchildren, four of whom are members of the Imperial family, and four great-grandchildren.

The prince is known as a scholar of ancient Oriental history and currently serves as honorary president of the Middle Eastern Culture Center in Japan and the Japan-Turkey Society.