LONDON — One photograph was taken by the Duchess of Cambridge, his mother, when he was just 3 days old.

The other was taken on the third birthday of his older sister, Princess Charlotte.

He is Prince Louis, fifth in line to the British throne, son of Prince William and great-grandson of Queen Elizabeth II and Prince Philip.

Kensington Palace released the first two official photographs of the newborn on Sunday, and there enough details about the images to satiate the appetite of royal fans.

One photo shows Princess Charlotte, the prince’s sister, planting akiss on his brow while he is sound asleep. That image was taken on Wednesday, the palace said, the day she turned 3.

She is wearing what the news outlets called a royal hand-me-down: a blue and white cardigan worn by her older brother, Prince George, 4, for a family portrait marking the queen’s 90th birthday in April 2016.

In the other photograph, Prince Louis, wide-eyed and looking calm, is clad in a white jumper previously worn by Charlotte soon after she was born, according to The Sunday Times. He is shown lying atop a cushion and a blanket embroidered with a rose.

That image was taken on April 26, three days after he was born, the palace said. (The duke and duchess celebrated their seventh wedding anniversary on April 29.)

The duchess, an art history grad, has released pictures to mark other milestones in her children’s lives, including George and Charlotte’s first days at nursery school.

Louis was born in the Lindo Wing of St. Mary’s Hospital in central London, weighing 8 pounds 7 ounces.

His full name — Louis Arthur Charles — was announced on April 27, and his parents formally registered the birth on Tuesday at Kensington Palace in front of an official from the Westminster Register Office.

When newborns in Britain are registered, details of the parents and their parents’ occupations are included for the record.

William and Kate listed their jobs as prince and princess of the United Kingdom.

The royal family is preparing for another big event: the wedding of Prince Harry and the American actress Meghan Markle.Alas, as the palace announced more details about the nuptials on May 19, it was learned that Louis would not be joining the rest of his family for the ceremony.