Monarchs, heads of state and PMs across the world, both past and present, have been sending heartfelt tributes following the death of Prince Philip, Duke of Edinburgh, at the age of 99. Spain's king and queen telegrammed "Dear Aunt Lilibet" to mourn the passing of "Dear Uncle Philip". Along with tributes from Europe's royal households, many Commonwealth nations praised his exceptional public service. They paid tribute to a life of duty, purpose, and devotion to the Queen. US President Joe Biden also sent condolences, hailing the duke's World War Two service, his environmental activities and charitable concerns, adding: "He was a heck of a guy... 99 years old, he never slowed down at all." Donald Trump, Barack Obama and George W Bush also sent touching tributes. The duke, whose death was announced by Buckingham Palace on Friday, accompanied the Queen during hundreds of overseas visits. 'Cherish the memories' Prince Philip had blood ties with a number of former or current European royal households, and many of their members have been sending condolences. The telegram from King Felipe and Queen Letizia of Spain was particularly poignant, sending "all our love and affection" to Aunt Lilibet (the affectionate name used by the duke for his wife) and Dear Uncle Philip. "We shall never forget the moments that we shared with him and the legacy of service and dedication to the Crown and the United Kingdom by your side," they told the Queen. Sweden's King Carl Gustaf was also moved, saying the duke had been "a great friend of our family for many years, a relation we have deeply valued". Swedish royal family spokeswoman Margareta Thorgren told the BBC the king and the duke had sailed together in England, adding: "That was the start of a great friendship between them." The Dutch royal family said they remembered Prince Philip with great respect, adding: "He dedicated his long life to the service of the British people and to his many duties and responsibilities. His lively personality made an indelible impression." Belgium's King Philippe said he and Queen Mathilde would "always cherish the memories of our warm encounters".