King Charles III on Thursday said he backed an investigation into the British royal family’s ties to slavery in the 17th and 18th centuries — an issue he takes “profoundly seriously,” according to a Buckingham Palace spokesperson. The significant announcement is believed to be the palace’s first instance of public support for research into the royal family’s much-debated involvement in the enslavement of African people. Charles, who ascended to the throne after the death of his mother, Queen Elizabeth II, last September, expressed support for the research after the British newspaper The Guardi...