Kate Middleton meets Luxembourg royals (2) The Duchess of Cambridge Kate Middleton meets the Luxembourg royal family and unveils an artwork in the capital's Place Clairefontaine as part of her trip to mark the 150th anniversary of the Treaty of London. Luxembourg gained independence in 1839, and in May 1867 a London conference was held, which resulted in the Treaty of London on 11 May 11 1867. IMAGESCOMPLETES VID1027544_EN