While ordinary grandparents had to go through court if they wanted custody of their grandchildren, the king had automatic legal custody of all his descendants and their minor grandchildren.
The kings have legal custody of their grandchildren, royal historian Marlene Koenig told News.com.au. in 2018.
This means Charles technically has custody of Prince William and Kate Middleton’s three children, Prince George, Prince Charlotte and Prince Louis, as well as Meghan Markle and Prince Harry’s children, Archie and Lilibet.
This 300-year-old rule may seem odd, and although it’s impossible for kings to take their grandchildren away from their parents, the law still technically exists.
Source : www.insider.com