Philip, who was a member of the Greek royal family in exile, has been at Elizabeth's full support since their marriage in 1947, when Elizabeth became queen in 1952, he gave up a successful naval career to support her.
The Duke of Edinburgh is associated with over 780 organisations, but he will no longer play an active role in attending their engagements.
Philip, also referred to as the Duke of Edinburgh, has been married to Elizabeth II for the entirety of her 65-year tenure as Queen of the United Kingdom. The 95-year-old will continue to attend any events scheduled between now and August, but will not accept any new invitations thereafter.
His well-earned retirement comes after 70 years dedicated service to Britain and Her Majesty, who has given him her "full support" to step down.
Despite rumors surrounding the announcement, a Buckingham Palace spokesman assured citizens there was "no cause for alarm" when it came to the health of Queen Elizabeth or Prince Philip, the Independent reported.
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A royal aide said of the Duke: "He's looking forward to enjoying more of his leisure time".
Royal watchers had been wondering how long the royal couple would continue with their schedule of appointments in their advancing years.
When contacted by Newshub, the Buckingham Palace denied those reports, saying both were "alive and well".
Following the announcement, British Prime Minister Theresa May paid tribute to the prince.
In 2016, he attended 200 events as he continued to represent the royal family with his own distinctive style.
Elizabeth and Philip appeared to be in good health Wednesday.
At an engagement at St James's Palace in central London with his wife yesterday, a guest told Prince Philip he was sorry to hear he was standing down.
Corbyn said the Duke of Edinburgh program, which encourages teenagers to take part in challenging group activities and community service, "has inspired young people for more than 60 years in over 140 nations".