Japan's Emperor Naruhito waves to members of the public on May 4

Japan's Emperor Naruhito waves to members of the public on May 4

Tomohiro Ohsumi/Getty Images

During this trip to Japan, President Donald Trump will be the first foreign guest for the country's new emperor.

Former Emperor Akihito, 85, stepped down in April, and was replaced by his 59-year-old son, Crown Prince Naruhito.

That means Trump and first lady Melania Trump will be Naruhito's first official foreign guests, and Trump's trip will be the first state visit of a foreign leader in Japan's Reiwa era.

Japan's eras mark who the emperor is and form the basis for the Japanese calendar system. Akihito presided over the Heisei era, which ended the day he stepped down.