British Prime Minister Theresa May led the tributes on Wednesday as Prince Philip, the husband of Queen Elizabeth II, attended his final individual public engagement after 65 years of royal duties. The challenge, which raises funds and awareness for the Royal Marines Charity, sees royal marines from around the country running 16.64 miles each day for 100 days, totalling a distance of 1664 miles. Prince Philip is Captain General of the Royal Marines, a title that is expected to pass to his grandson Prince Harry.
He was also met with cheers as he was handed the Challenge baton.
As the Queen's husband of almost 70 years, Prince Philip is the longest-serving British consort (companion to the sovereign).
This came even as the Duke of Edinburgh, 96, prepared for his final solo engagement in a ceremony at Buckingham Palace, before enjoying time away from the hectic royal schedule.
In retirement, the Duke will likely enjoy more leisure time at Windsor Castle in Berkshire - he is an avid carriage driver and enjoys oil painting.
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Having a famous spouse wasn't unusual for her, as Barbara Sinatra's first marriage was to one of the Marx Brothers, Zeppo. Barbara married Frank in 1976 and remained his wife for almost 22 years - the longest of his 4 marriages.
The Daily Telegraph has accidentally published a story incorrectly stating that Prince Philip is dead.
Prince Philip is involved with over 780 organisations, in the capacity of patron, president or member.
In the summer of 1946, Philip asked the King George VI for his daughter's hand in marriage, delaying the public announcement of their engagement until Elizabeth turned 21 the following April.
It was announced in May that Philip would no longer undertake his own programme of engagements, though he may still accompany the Queen at certain events from time to time.
Philip, who's the longest-serving royal spouse in British history, has carried out an astounding number of duties over the last six decades.
They have four children and eight grandchildren.