Thousands of members of the Royal Navy, Army and Royal Air Force have taken part in a parade and flypast to mark the Queen's Diamond Jubilee.
The event was designed to reflect the close relationship between the Queen and the armed forces.
More than 2,500 servicemen and women marched past the Queen in Windsor Castle before mustering in an arena.
A flypast of 78 current and historic aircraft, including helicopters and the Red Arrows closed the event.
A tribute by the armed forces to the monarch during a Jubilee year is an established tradition, with similar events held for Queen Victoria and King George V in which the Royal Navy took centre stage as the largest service.
The Queen reviewed each service at separate locations for her Silver Jubilee in 1977 and attended a tri-service event at Whale Island in Portsmouth for her Golden Jubilee in 2002.
The parade and muster in Windsor was the first time all three services have visited the Queen for a dedicated event.
The event started at 11:00 BST with a flypast of nine RAF Typhoons over Windsor Castle.
Members of the Navy were the first of more than 2,500 personnel to parade through the castle Quadrangle.
They then headed down through the town, where one estimate put the crowd at 20,000, before entering Home Park and mustering in a specially-built arena.
The parade past the Queen was just over half a mile long and lasted about 15 minutes.
The space inside the castle's walls was chosen for the marchpast as it provided an intimate setting, bringing the troops within two to three metres of the Queen.
The Queen and the Duke of Edinburgh arrived by car at the muster - after driving through Windsor streets lined with well-wishers - where an audience of 3,800, including royals, veterans and family members were gathered.
A drumhead service (where a makeshift altar is formed by three tiers of drums) then took place, followed by a speech by the Chief of the Defence Staff, General Sir David Richards.
Addressing the monarch, the general said: "Your commitment to our nation is an example to us all.
"For six decades your devotion to duty, sense of honour and pride in our country have set the standards to which your armed forces constantly aspire."
Following this, the Queen gave a brief speech in which she said: "It is a tradition of very long standing that members of our Royal Family are intimately associated with the armed forces and have been proud to serve in all three services."
New pieces of music written especially for the event were then performed, alongside old favourites such as Rule Britannia and Land of Hope and Glory.
A tri-service flypast of 78 aircraft including helicopters, the Lancaster and Spitfires of the Battle of Britain Memorial Flight, Hercules, VC10 and Tornado aircraft, Hawks and Tucanos and Red Arrows closed the event.
Air Vice-Marshal Murray, who organised the event, said he had been keen to give the Queen a day she would enjoy.
He added: "There are so many good activities going on as part of the Jubilee celebrations and this is something that only we, the military, can do."