US President Joe Biden has congratulated Denmark’s new King Frederik X and honoured the achievements of the long-serving monarch Margrethe II. Margrethe’s 52-year reign had spanned the reigns of 10 US presidents, “an era during which the Kingdom of Denmark and the United States moved closer together as security and trade partners, while the bonds of friendship between our people grew ever stronger,” wrote Biden. Margrethe had set an “an incredible example of selfless, principled service” with her commitment to her country over the past five decades, Biden said.