Lord Ivar Mountbatten and partner James Coyle.

Washington - Meghan Merkle made history in May as the first black and American woman to marry into the British royal family. 

Less than a month later, the royal family announced plans for yet another historic union: Lord Ivar Mountbatten will marry James Coyle, his partner of two years, in the monarchy's first-ever same-sex wedding later this summer.

In an interview with the Daily Mail, Mountbatten said the wedding would be held in a private chapel on his estate in Devon. While the members of the core royal family - meaning the Queen Elizabeth II and her direct descendants - are not expected to attend, the couple has the full support of the royal family, Mountbatten told the Mail.

Mountbatten, a third cousin of Queen Elizabeth II and descendant of Queen Victoria, became the first Royal to publicly identify as gay in 2016. He has three children with his former wife Penny Mountbatten, who has been openly supportive of her husband's relationship with Coyle. She said last week that she plans to walk Mountbatten down the aisle at the suggestion of their daughters.

While Mountbatten will go down in history books as the first Royal to marry a member of the same sex, news of his marriage isn't raising eyebrows in the United Kingdom. 

Mountbatten is also sufficiently distant from the throne that his marriage does not raise any issues involving the constitution, said Jonathan Thomas, the publisher of Anglotopia.net who has been covering the British monarchy and British culture since 2007.

The royal family still abides by a law passed in 1772, titled the Royal Marriages Act, that requires the first six people in the line of succession to receive permission from the ruling monarch before they marry. (The Queen gave her formal consent to Prince Harry and Merkle in March.) 

Because Mountbatten is so far away from the line of succession, and because he already has children, his marriage to Coyle has little bearing on the leaders of the family.

Nonetheless, Mountbatten has broken new ground, Thomas said. "Change happens a lot around the edges, and as people further from the center make changes, these [changes] will increase toward the center," he said.