Japan's Emperor Akihito and Empress Michiko marked their 50th wedding anniversary Friday with a series of celebrations, including a gala party with 100 couples who are also celebrating 50 years of marriage.

The royal couple wed on April 10, 1959, when Akihito was crown prince.

"Throughout our marriage, the empress has understood the significance of my position and duties, and in private life, she has always stood by me and has been very devoted to my family," Akihito, 75, said during a news conference Wednesday ahead of the anniversary, with his 74-year-old wife sitting next to him.

"I know she has encountered sadness and difficulties many times, but the empress has endured them with great patience," the emperor said. "If there is something that I would give her for our 50th wedding anniversary, it would be a certificate of gratitude."

Their wedding was a national sensation that also marked the beginning of Japan's postwar economic boom.

Michiko, who was the first commoner to marry into the royal family, became a national icon of gracefulness and intelligence. She said she felt insecure and anxious to join the royal family, and the 50 years together were "long and hard at times."

"It's like a dream to be able to celebrate the day of our golden wedding right next to the emperor today," Michiko said.

Several events were scheduled to mark the event, including the evening party, a private family dinner and visits with government officials. The public also turned out to sign congratulatory guest books outside Tokyo's Imperial Palace.

Palace life in Japan is deeply shaped by tradition, and members of the imperial family are rarely able to speak their opinions or show their casual side in public.

Japan's royal family has been hit by a spate of illnesses recently, with both Akihito and Michiko cutting back their official appearances because of stress-related health problems. Masako, the wife of their son Crown Prince Naruhito, is still recovering from a form of depression.